Posted By Western States Roofing Contractors Association,
Monday, March 12, 2018
Updated: Monday, March 12, 2018
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By: Brian P. Chamberlain — Carlisle Construction Materials
In today’s market we find significant focus from building owners on sustainable and durable roof installation. To accomplish this goal, building owners look to designers to specify durable products, supply qualified installers, and have material manufacturers offer long-term warranties. The first two conditions can be controlled and monitored to make sure that the installation is verified to have the proposed quality. The roofing warranty is looked upon by building owners and specifiers as a way to get a guarantee that these first two conditions are met. It’s very similar to an architect specifying a white membrane roof with the expectation, without any true consideration, that white membrane will help save energy associated to the operation of the building and in turn reduce the carbon footprint of the building. Unfortunately, without fully understanding how geography plays a major role in energy performance, the specifier may not design the roofing system to offer true energy performance and inadvertently increase other concerns. Studies have shown white membrane roofs need to be designed according to the building location geographically 1 . With the same consideration, it should be understood that warranties are tools to assist in selling of roofing manufacturer’s products and may not be an indicator of durability.
1 Samir K. Ibrahim, “Sustainable Roof Design: More than a Black-and-White Issue”, RCI - Building Envelope Technology Symposium, San Diego, CA, 2009
To understand this fully, we need to review how roofing material manufacturers promote warranties and then review the fine print of what they are covering within the language of the warranty.
DURABLE ROOFING ASSEMBLIES
The basic premise of a long-term warranty can be seen by how a manufacturer’s specification promotes sustainable assemblies. One of the first products we find typically required for longer term warranties is thicker membrane. Where shorter term warranties allow the use of thinner membrane such as 45-mil thick, longer term warranties are published with thicker membranes such as 90-mil thick. There is significant data to show that thicker membranes are superior to thinner membranes. For comparison, Figure 1 shows the results of a Federal Puncture Test with non-reinforced EPDM. The EPDM membrane with a 90-mil thickness has a 60% increase in puncture resistance over a 45-mil membrane.
Another indication of durability can be found by testing roofing materials within the Xenon Arc Weathering Test (ASTM G 155). In Figure 2 the results for a reinforced TPO membrane can be seen based on kJ/mÇ. The 80-mil thick reinforced TPO has 42% greater weatherability than a 45-mil thick reinforced TPO.
These results can be then compared to the proposed building location based on expected radiant exposure to determine the minimum design consideration. But just like building codes, to offer a durable long lasting assembly, the designer should go above the minimum. In most cases, the designer will find this parameter already required by the roofing materials manufacturer.
As membrane thickness is promoted by manufacturers through longer term warranties, other components of the roof assembly are promoted above the typical shorter term warranties. The splicing of EPDM membranes are specified to be either wider seams with tapes or factory applied tapes, while thermoplastic membrane assemblies promote overlayment of the seams with additional welded products. Longer term warranties promote factory manufactured flashings, such as pipe seals and premade curb flashings. Multiple layers and thickness of insulation are important to reduce energy costs in the long term and performance of the building. A single layer of insulation may assist in the initial sale of the assembly, but the typical gap left behind with energy loss could be significant over the long term as shown in Figure 4.
As technology improves products, they are promoted for longer term warranties. New insulation facers have been developed that offer moisture, mold, and wind uplift resistance. Figure 5 shows the typical uplift results between a fiber board, a standard black paper facer on polyisocyanurate, and a fiberglass coated facer on polyisocyanurate.
Manufacturers try to take into account foot traffic and unusual weather conditions that a roof assembly may experience over a long term warranty, so their roofing specifications include cover boards or higher compressive strength insulation to offer additional durability.
Besides warranties promoting thicker membranes, superior cover boards/insulations, and pre-fabricated accessories, there are incentives that can be included within the warranty, such as accidental puncture coverage, hail coverage, and reflective stability, if promoted enhancements by the manufacturer are specified. Some warranties will include other components, such as skylights, photovoltaic arrays, walking decks, and garden roof materials. In the case of the photovoltaic arrays, walking decks, and garden roofs, a membrane roof assembly’s components are specified to handle these additional uses of a roof area. If specified properly the manufacturer can include overburden removal and replacement within the warranty coverage, giving the owner the peace of mind that if a leak should occur, the investigation will not cost him anything additional.
WIND SPEED WARRANTY COVERAGE
Warranties also promote higher wind speed coverage and often incorporate cover boards, higher compressive strength insulation, and higher fastening density of the insulation to deal with long term performance. At times the specifier will find that the metal edging, which is the first line of defense against any wind storm, must be pre-manufactured and has been tested following the criteria within the ANSI/SPRI ES-1 and exceeds the International Building Code (IBC) standards. In higher wind locations, “Storm Strips” (a row of securement around the perimeter) might be suggested with the consideration to minimize storm damage.
For mechanically fastened assemblies, longer term warranties are available by specifying reduced spacing between rows of securement to increase uplift performance and fatigue on the roofing membrane. When special wind conditions are necessary for a warranty, an air barrier may be installed below the insulation on a steel deck to assist mitigating the interior pressure from the uplift, adding to the overall performance from wind.
This effort by a manufacturer to specify thicker membrane, better insulation, durable accessories, and incentives for additional coverage with a longer-term warranty increases the manufacturer’s reputation to the building owner in a positive manner. The building owner in turn assumes that the manufacturer’s warranty is an indicator of responsibility by the manufacturer and the relative life expectancy of the roof system. Unfortunately, warranties are used more as a marketing tool to assist in selling of roofing materials so even though a long-term warranty is preferable, the owner needs to review and understand what the warranty is actually offering as coverage.
After researching numerous published warranties and the phrases within, some warranties with equal duration do not match up with coverage. How many times have we heard, “Your 20-warranty requires additional components unlike your competitor? Isn’t all 20-year warranties the same?” Though the length of the warranty could be important, how each warranty is worded for coverage could be different allowing one roofing manufacturer more flexibility to deviate from the published specification by substituting lower performing products to have a more competitive advantage. To make sure the roofing installation has the same quality installation from either manufacturer, it becomes necessary for a building owner to understand what a warranty covers beyond the duration.
Once a building owner is convinced to read what is within a warranty, it can be difficult for the building owner to interpret the language. One of the reasons this is a problem is because warranties are written by the membrane manufacturer’s lawyer. The lawyer’s goal is to limit the liability of the membrane manufacturer. To make sense of what the building owner is actually receiving as coverage within a warranty, we need to focus on specific parts within a typical warranty.
Warranties are most often broken down into two parts. The first part is what the warranty covers which is typically referenced as the “roofing system”, defined as membrane, insulation, fasteners, flashing, and whatever additional components the manufacturer sells associated with the project. In my research I have found that the definition of “roofing system” can be altered. In one warranty the definition of the “roof system” was limited to just the roofing membrane without referring to any other associated purchased materials. Even though the warranty is titled Roof System Warranty the coverage only included the membrane, which is very similar to a material warranty. Though there is nothing wrong with a manufacturer defining a roofing system this way it can be misleading.
As mentioned, the first part also lists what else may be included under the coverage of the warranty. Sometimes a manufacturer does not sell a specific product required for the assembly, but is unwilling to lose the sale of their assembly, so they list these products on the warranty so as not to be excluded from the sale. This offers the flexibility necessary to keep the manufacturer in the prospect of winning the project. At the same time, they may list products that they do not cover, or the opposite simply not list such products at all, leaving the building owner with a potential hole in his expected coverage. An example would be a membrane manufacturer has the ability to sell all the components of an architecturally specified installation except for the asphalt required for insulation attachment. In this case, the manufacture may be willing to take the responsibility for the asphalt by listing this component on the warranty. If the manufacture does not want to cover the performance of the asphalt he may still offer the warranty, but list the asphalt as excluded from the coverage. Or the manufacturer will offer his warranty, but simply not mention the asphalt at all within the warrantable components. Again, none of the above is wrong, but it does reinforce the need for a building owner to read and understand the warranty coverage.
The second part is most often called “Terms, Condition, & Limitations” of the warranty. This section of the warranty can include numerous phrases that should be looked at closely to understand what is being offered. In this section, the membrane manufacturer offers details on how he will assist in paying for repairs. Some of the most common phrases have been “pro-rated”, “limited to original cost”, and “no-dollar limit” financial coverage. “Pro-rated” starts off with the original cost of the installation and then that amount is reduced a percentage each year based on the duration of the warranty. “Limited to original cost” limits the manufacturer’s financial responsibility to the initial cost excluding any inflation that could happen over the long term. “No-dollar limit” is the original cost with the inclusion of inflation. To see the difference between the two, Figure 6 shows an example of a 25-year pro-rated warranty versus a 20-year no-dollar limit warranty. Even though the duration of the longer warranty is 5 years, upon a catastrophic failure occurring at the 14th year the replacement cost to building owner is more than the original cost of the roof system. In this case, duration did not equal coverage.
In addition to how the warranty payment will be handled, the second section of the warranty includes the wind coverage. Wind speed coverage is a moving target. Historically, roofing system warranties did not offer this type of coverage. When it was thought to assist in the sales of the roofing system, warranties began to use words such as “Gale Force Winds”. The definition of this term can be found on Figure 7, a portion of the Beaufort Wind Scale.
Referring to Figure 7 one might be surprised to see that there are four different “Gale” type winds. The term “Gale Force Winds” referenced in some warranties is considered to be defined by the manufacturer as “Fresh Gale”, offering coverage up to 39-46 mph wind. Though the industry accepted this concept, owners demanded to know what the exact wind speed number might be, so some warranties started to actually list the wind speed as “not to exceed 55 mph”, which we can see on Figure 7 is “Strong Gale” wind coverage. When longer term warranties were introduced, they included an option of possible higher wind coverage, so 72 mph was offered, which is one mile per hour short of a hurricane.
With the introduction of wind coverage, building owners and specifiers have become confused about how this might relate to building codes 2. The bottom line is that they have no relationship to each other. The International Building Code does not require a wind warranty on roofs, only that they meet the allowable uplift pressures determined and calculated by using the ASCE 7. In this same respect other components such as structural walls, decking, etc. must also meet this calculated pressure, but none offer wind speed warranty coverage. Since this is the case, a warranty wind speed is not based on ASCE 7 or the ANSI/FM 4474 uplift rating test. Warranty wind speeds are typically based upon the manufacturer’s installation experience and the demands of the market.
2 Marty Gilson & Brian Chamberlain “Roofing Warranty Wind Speed Coverage versus Local Building Codes, Local Wind Speeds, and FM Global: Solving the Mystery,” Northern Illinois CSI Link, May 2007.
In an attempt to reduce misunderstanding roofing manufacturers can offer warranty wind speed coverage in miles per hour that equal the local wind speeds as published by the ASCE 7. It is important to remember that the ASCE 7 is referenced under the Performance or Quality Assurance section of a bidding specification, while the warranty wind speed needs to be listed in miles per hour in the Warranty section. If the requested wind speed coverage is not in the Warranty section, the contractor will bid the project at the minimum wind speed warrant coverage offer by the manufacturer. Typically when this is discovered, the roofing system has been installed and may no longer qualify for the higher wind speed warranty.
Values are nominal design 3-second gust wind speeds in miles per hour (m/s) at 33-ft (10m) above ground for Exposure “C” category
Though manufacturers include higher wind speed coverage if requested, the wording of their standard coverage can be worded to limit their liability, while at the same time offering the illusion that they are covering more. An example of this would be not listing the miles per hour in the warranty but using words like Gale Force Winds (39-46 mph). Another example would be calling out wind coverage up to “Beaufort Scale #8” (39-46 mph). In both cases, the miles per hour coverage is hidden by words and must be clarified.
Besides wording, where the wind speed is measured can be creative. Most warranties are measured at “Ground Wind Speed”, which is 33-ft or 10 meters from the ground surface, the same height at which airports measure wind speed. Some warranties have the phrase “Rooftop Wind Speed". The higher the roof area, the greater the wind speed, so if you are considering wind speed coverage, ground wind speed offers better coverage on a higher building. As an example, if the building is 30 to 40 feet high there is practically no difference in the coverage, but it can make a huge difference on high rise roof areas. In Figure 9, a 300 ft high roof area with a rooftop wind speed of 80 mph, the ground wind speed would be 55 mph, while a ground wind speed of 80 mph would actually cover winds up to 118 mph for the same building.
EXAMPLES OF WARRANTY LANGUAGE
The examples that follow are sample warranty wording that was discovered on different membrane manufacturer’s website samples.
In one manufacturer’s 30-year System Warranty, the financial liability of the manufacturer was “limited to the original cost”, so if the roof system cost $100,000 that would be the maximum the manufacturer would pay, not including inflation. In addition, it was listed in the warranty that the owner pays for two inspections every five years in addition to any cost for repairs required by the manufacturer. This warranty did not list any wind speed coverage, so we can assume that if the roof system is damaged by any wind greater than zero, it is not covered under the warranty. And finally this warranty was “non-transferable”. Though most schools and government buildings typically will never transfer ownership, a warehouse or office building could change hands within the 30-year duration of the warranty, leaving the new building owner with no coverage at all.
A 25-year warranty sample found on the web began by stating that this warranty only covered the membrane. If deterioration of the membrane was discovered, the manufacturer’s responsibility is to ship and replace “defective” membrane. The cost to the manufacturer was limited not to exceed the original cost of the membrane and shipping to the building site. Though it did offer wind coverage up to a full gale force winds (46 mph?) it was clear that it did not include any failure of the substrate under the membrane or failure of any other roofing components. How would wind cause the deterioration of the membrane? As a final note, the membrane manufacturer stated it would not cover the workmanship by the installer.
Another long term warranty (20-year) requires the building owner to schedule inspections with the manufacturer after 2, 5, 10, and 15 years at the owner’s expense. It did publish wind speed coverage less than 73 mph, which the Beaufort Wind Scale defines as being the lowest miles per hour for a hurricane. This warranty again was “nontransferable” and the coverage was “pro-rated”, so a $100,000 roof installation would loss coverage year after year.
One manufacturer published their warranty including similar language (“nontransferable” and “limited to the original cost”), but this 20-year warranty offer wind coverage with “gales excluded”. Returning back to the Beaufort Wind Scale, we see that gale force winds begin at 32 mph, so in reality, this warranty only offered coverage up to
Though there are many more warranty versions, this last one I offer is called a 20-year System Warranty and for the first 10 years has coverage is very similar to a “nodollar-limit” system warranty. But in the body of the warranty it states that after 10 years, the warranty becomes a “pro-rated” material warranty (labor not included) and lists the actual percentage of coverage. The Figure 10 below gives you an idea of financial assistance offered by the manufacturer, assuming the original installation cost $100,000.-.
20 Year Warranty % Coverage Cost of Installation $100,000.-
1st – 10th Year 100% Total System $100,000.-
11th Year 80% of Material $12,000.-
12th Year 60% of Material $9,000.-
13th Year 40% of Material $6,000.-
14th – 20th Year 30% of Material $4,500.-
PHRASES TO LOOK FOR
When assisting a building owner in the design of the roofing system to achieve the goal of durability, knowing the type of wording to look for in the warranty can be invaluable. Here are a few phrases that may be encountered:
• System Warranty: Where a Material Warranty will only cover the sheet good of the roofing system, a System Warranty typically is defined as covering all products installed offered by the manufacturer and includes the labor to install the referenced materials.
• Is the warranty transferable to a new owner upon the sale of the building or is there a limitation and stipulation that should be reviewed based on the owner’s plans for the future?
• Wording within the warranty may require the building owner to pay for periodic inspection by the roofing material manufacturer, including any costs associated to repairs found necessary during those inspections.
• A notation of maintenance required by the building owner, if not performed by the building owner could void the warranty. Though the above are some of the terms that should be reviewed closely below is some of the more favorable language that should be included.
• The warranty offers “full coverage” that includes labor to install and repair if necessary and material costs.
• “No Dollar Limit”, so if a catastrophic problem occurs and it is at the fault of the roof system, replacement of the roof system will cost the building owner nothing.
• The warranty should be “transferable” and there should be clarification of the cost and inspection requirements.
• Look for “wind coverage”, which should be listed in miles per hour and where the wind speed is measured should be specified.
• Depending on the building owner’s needs, possible additional coverage, such as hail, accidental puncture, or reflectivity should be included. This type of coverage is available but is not typically included in standard warranties. The building owner must have these needs referenced in the warranty section of the building specification.
In conclusion, the assemblies specified in association with a long term warranty do offer durable options for the building owner. They promote thicker membranes, stronger substrates, and better combined assemblies to match the length of the warranty and expectations of the building owner. Unfortunately, the published warranties need to be reviewed closely to make sure they match what is being offered.
One way a specifier could assist the building owner would be to review the warranty section of the proposed architectural specification to make sure some of favorable phrases listed earlier are incorporated in this section. Another would be to require a sample copy of the proposed warranty to be included with all bidding documents, so coverage can be reviewed along with cost. If anything within warranty wording seems amiss based on the building owner’s needs, clarification can be requested in writing from the manufacturer to clear up any confusion.
Keep in mind, if one manufacturer’s coverage is different than his competition, he can offer an assembly based on his warranty liability, the result could be a more cost competitive system with the building owner unaware of the potentially loss of warranty coverage. With this information, the specifier can guide the building owner away from using warranties as design criteria and focus on quality materials, proper assemblies, and verifiable workmanship.
Karen Warseck, “Roofing Warranties: Always Read the Fine Print,” Building Operating Management, February 2008.
Chuck Marvin, “Roof Warranties Moving Past Clichés,” Interface, April 2011.
Samir K. Ibrahim, “Inside the NDL,” PowerPoint Presentation, February 2006.
NRCA, “Roofing Warranties,” http://www.nrca.net/consumer/warranties.aspx
Republished with permission.
Posted By Western States Roofing Contractors Association,
Tuesday, February 20, 2018
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by: Todd Miller - Isaiah Industries, Inc.,
Todd Miller is President of Isaiah Industries, Inc., a leading manufacturer of specialty residential metal roofing. His personal website, www.asktoddmiller.com, is a great resource for answers to your questions about roofing and ventilation.
Why is there reason to be concerned that residential metal roofing products are specified and used properly? First of all, the metal roofing industry continues to enjoy rapid growth. Current market share is estimated at 14% of the roofing market and, depending upon where you live and exactly what sector of the roofing industry you serve, you may feel like the market share is considerably higher than that. This is much higher than 15 or so years ago when market share nationally was only around 2%.
So, what is driving this growth? Increased awareness is playing a big role. A rising tide raises all ships. Property owners see more metal roofs and they want to become a part of the trend. They read about metal roofing on the internet and see photos of beautiful roofs. Once they learn about some of the other benefits of metal roofing, they don’t want to miss out on those either. I think that what we’re seeing in metal, especially in the residential arena right now, is part of an evolution toward better building materials that has always existed and is going to continue to occur.
Those benefits that property owners appreciate include durability, wind resistance, and fire safety. We’re also seeing metal being selected for its low weight compared to other roofing materials, especially on older structures. There is also great interest in the energy efficiency of metal roofing, this being driven heavily by the federal tax credit that, for several years, was in place for reflective metal roofing. And, in general, homeowners really like the green benefits of metal roofing including not only the energy efficiency but also the recycled content of the metal, the 100% recyclability of the products at the end of their life, and the ability in many instances to install metal roofs over old shingles.
As a part of this increased use of metal roofing, we’re seeing more manufacturers and also more contractors entering the arena. And all of those new players come with some learning curve still ahead of them. Even the most experienced of us are always learning. That’s why education and information are so very important.
Many roofing contractors are interested in metal right now. In fact, if you go to just about any roofing contractor’s website, or look at the lettering on their truck, there is some mention of metal. Yet almost every day I hear of stories of contractors advertising metal who can’t answer the questions about metal roofing that are posed to them by architects or homeowners. It’s also not uncommon for me to hear that if a prospective customer asks them about metal, they just downplay it and steer them instead toward their “bread and butter” product, whatever that might be.
Property owners are also increasingly intrigued about metal roofing yet, with them, there’s something even more dangerous going on than just lack of information and not knowing where to go for education. The worst thing about property owners is that they assume all metal roofs are the same. Sadly, they don’t even know what to look for nor what questions to ask! So, they are often going along with recommendations from their contractor or their lumberyard or big box, even though they don’t really understand the product being sold to them. Their expectations may be way too high, sometimes leaving them badly disappointed when the product doesn’t look or perform as they had expected.
So, the end result of this lack of good training, good information, and appropriate resources is two things:
1) Products are being used incorrectly – they are being used on jobs and in ways for which they were never intended to be used; and
2) Products are often being installed incorrectly – fastened wrong, cut wrong, flashed wrong -- you name it. All of these are bad things that lead to unhappy customers.
So, that brings us to this topic of specifying the best possible option for every metal roof installation. Because it’s a bit like eating an elephant where you have to do it one bite at a time, I will review what’s available in metal roofing today including where it works and where it does not work.
There are numerous key considerations that must be considered on each and every project where a metal roof is being considered. Keeping these things in mind as the project is evaluated will allow the best metal roof option to be called for. Before we start digging into product details and limitations, let’s take a look at some of the Key Considerations when recommending a particular metal roof. These are the very important things to be aware of on every project before you decide which product will be best for that roof.
Roof Geometry. Are your salespeople – those out helping property owners assess their needs and determine an appropriate solution – experts at considering the overall shape or configuration of a roof? Are they trained and looking for things like flared gables – where the roof is wider at the top than the bottom? Are they thinking about water and potentially even snow and ice that will shed from upper roofs onto lower roofs? Are they looking for non-90 degree hips? Have they ever brought in contracts for jobs with complex things on them like eyebrow windows or barrel dormers … and they’d not really given any thought to how time consuming the proper installation of those areas will be? All of these things play huge roles in making sure the proper product is being specified and that the contractor has the resources to carry out the project specifically – meaning that the contractor is getting paid enough to do the job well. Being able to assess and evaluate roof geometry and how metal roofing will work with that geometry is critical.
Water Flow. This is another big one. You may think you’re doing great by specifying a snap lock standing seam with a 1.875” tall seam but then completely miss the 25’ rafter length on a second story that is going to drop all of that water onto a first floor roof, making it all land in one 15” wide standing seam panel on a 3:12 pitch. Do you know how many times I’ve been consulted on roofs where they couldn’t track down a leak and it was just because they had way too much water flowing down one standing seam panel, and it’s flooding out? When evaluating roofs and recommending roof systems, as I am sure you have all heard before, you must think like a rain drop.
Air movement. This is especially critical in areas with high wind potential. Most folks in the roofing industry know that the side of the roof that takes the brunt of uplift pressures in a severe wind event is not the side of the roof that faces the wind – it’s actually the back side of the roof which gets the effect of wind rushing over the roof and curling around on the back side, trying to lift the panels off the roof. Sometimes the geometry of the roof also contributes to high uplift areas in certain places. So, how do you deal with that? Well, in some cases, you can consider increasing fasteners or something in the areas that are most likely to have damage from high winds. Regardless, a roof must be built to sustain the winds it will endure. Understanding those wind dynamics is critical.
Attic Ventilation. While ventilation usually has more to do with how the roof is installed than what product is being installed, it’s still a critical consideration. Here are questions that your estimator or salesperson should be thinking about on every project. Are there special ventilation needs here beyond what is even required by code? Is there animal confinement going on? Do they have a lot of house plants? Ventless gas stove? Wet crawlspace or basement? Once you consider those, then you can begin to investigate … does the ventilation meet code? Is it evenly balanced between intake and exhaust or perhaps even a little pressurized in the attic due to a slightly higher level of intake? Do you need to add exhaust vents to the roof? Do you need to include a package with intake vents, or clean the insulation back from their intake vents? I don’t need to tell you about the number of lawsuits out there pertaining to mold in homes and other buildings. If you leave a home without proper ventilation, even if it was that way when you arrived, you’re at risk if mold develops in that structure and the homeowner and their insurance company start suing anyone and everyone who have ever touched that house. And, let me give you an extra warning here … let’s say the structure is not vented per code but they have never had a condensation problem before. Can a metal roof, if vented the same as the previous roof, cause problems that did not exist before? Actually, yes, it can. Because the metal roof will drop the roof deck temperature a couple of degrees from what it was previously, condensation might occur that did not occur before. And if that building is made more air tight in the future such as by adding a house wrap or new windows or doors, that will increase the amount of moisture that ends up in the attic, again increasing the risk of condensation occurring.
Trees Around The House. The first thing that trees around a house tell you is that there will be leaves or pine needles on the roof. So, as the roofer, how will those leaves and needles get off the roof without damage to the roof or without having them clog up your roof system? This is where specifying a roof system with only open valleys comes into play. If you install a roof system with closed valleys designed to carry water beneath the roof’s surface, those concealed waterways are going to clog up with debris and there are going to be major problems on the job. Rotted out eaves and other things.
What is another thing that trees tell me? That the roof is going to be prone to tree sap, or at least airborne fungus. So, I am going to want to specify a metal roof that has a coating on it that’s as resistant as possible to dirt and fungus. Otherwise, in a few years, you’re going to have a very unhappy customer and a situation that is a black eye for the metal roofing industry.
Aesthetics. Nine times out of ten, if you send me driving down a neighborhood street and tell me that there is a metal roof on a home on that street, I will be able to tell you which house it is on long before I can see the roof. How can that be? Because most metal roof customers care very much about the aesthetics – the beauty – of their homes. So, I will recognize the house based upon the landscaping, the manicured lawn, or perhaps a fountain or other lawn statuary.
So, if you have a prospective customer who cares about how their home looks, what are you going to do? Pull out the samples of your prettiest product. Maybe use Visualizer software from your manufacturer to help them see what their home will look like after the roof is completed. You’re going to do all you can to prove to them that their home will look phenomenal with your roof.
Here’s another interesting thing on aesthetics. I was contacted recently by a homeowner who was very unhappy that their contractor had sold them what they felt was an ugly metal roof. And they were so upset that they were trying to put a dollar amount on how much this ugly metal roof (and it really was not appropriate looks-wise for their home) was decreasing the value of their home so that they could deduct that from their final payment on the roof. They were playing with a number around $9000 when they contacted me.
Energy Efficiency. A big part of Needs Analysis with a property owner should focus on whether they’d like to make their home more energy efficient and, if so, how they’d like to accomplish that. Generally speaking, if they want to save energy in the winter, that is done by increasing the insulation on top of their home’s ceilings – holding the heat in. If the attic is vented according to code, which helps to prevent ice dams on roofs in the winter, then once that heat reaches the attic, it is exhausted out. Summer energy efficiency is achieved through reflecting heat away from the home, using thermal breaks to stop conductive heat transfer from the roof into the attic, and then, finally, by using ventilation to get rid of any heat that does make its way into the attic. Metal roofing meets these criteria well through the use of heat-reflective finishes, the integration of thermal breaks (small air gaps) between the metal roof and the roof deck, and by integrated ventilation. The thermal breaks I have mentioned work much the way the small airspace works between two pieces of glass in a thermal pane window. They stop conductive heat transfer. Metal shingles usually have an integrated thermal break. Vertical seam metal roofs can accomplish a thermal break by being installed on battens, if the product allows for that, or sometimes by using special clips that lift the panel slightly up off of the roof deck.
Weather Extremes. If you live in a hot climate, you will want to offer metal roofs with heat reflective coatings. If you live in an area prone to hurricanes, you’re going to do special things to prepare for wind events. In an area with lots of seismic activity? A low weight metal roof may be appropriate. Ice and snow – again, you will be looking at ventilation and at a roof system that won’t trap ice on the roof. You set yourself apart from your competitors, serve your customers with excellence, and ensure successful roofing projects by strongly considering the weather dynamics before recommending one metal roof type over another.
Other key considerations. When I train salespeople how to sell metal roofs, I teach them how to help homeowners set their Purchasing Criteria for the new roof. What are the homeowners’ hot buttons? What do they care about? What benefits will raise the value of the roof enough in their minds to justify the price? Is it durability, energy efficiency, added home value, beauty? Something else? What are the things they really want to accomplish with their roof investment? This is all determined very purposefully during the Needs Analysis part of your in-home presentation and, once you know these things, you can tailor your presentation to really build value in these areas. These things also become a critical tool that you will use when it comes time to close the deal because, as they weigh their decision, you can remind the property owners of the Purchasing Criteria they set, and what it will take to meet those goals.
Maybe this all seems like a lot to think about on every job. Maybe it seems like a lot to expect of your salespeople each time they meet with a prospective customer. But, is it really? I mean, after all, what are the risks if we don’t evaluate and assess these things – as well as many other things – in order to propose the roof system that will best serve the structure and its owners? Here are the risks. They aren’t small.
Worst case is you install a system that fails. Now, keep in mind, for most property owners, a metal roof is a significant investment. You do something that causes leaks to start popping up – perhaps even leaks that were never there before, and you have one unhappy customer. Worse, yet, what if those leaks are over their grand piano? Or their new gourmet kitchen? Anyone ever been there before? Anyone ever hear of an unhappy customer hitting social media and Ripoff Report to try to “take down” a contractor. I hope you have never experienced any of those things but, if you have, you know that it gets real ugly real fast. So, one risk to not properly evaluating the job and then recommending the right system is failure—call-backs, repairs, perhaps even replacement. Because, I have to tell you something – if you install a metal system on a roof that is flat-out inappropriate for that home or other building? There’s no fixing it … no amount of spit shine or elbow grease is going to make that metal roof that was intended for a 3:12 pitch roof work on even a 2.8:12 let alone a 1.5:12.
Next thing, of course, is an unhappy customer. Let’s say that what goes wrong is, by some miracle, something that you can easily fix. Even after the repair, you probably still have an unhappy customer. And, what’s more, because the metal roof was so unique, all the neighbors were watching. Now, they know that you messed up, too! Word travels fast, doesn’t it? And, an unhappy customer can easily mean you don’t get paid, you end up in court, and you don’t get referrals from that job! Worst case, just one messed up, ill-advised, improperly-specified metal roof, and you can create a situation that ruins a market for metal roofing for several years!
Okay, none of us wants any of that to happen, do we? So, in order to make sure that the right metal roof product is being used on each and every job, here are key things to consider:
The various profiles, or looks and style of metal roofing
Fastening and attachment Methods
By understanding the above things fully, then, based upon what you figured out during that earlier evaluation, you can know what sort of metal roof will be best for the project you’re on.
Let’s discuss Profiles first – the general designs or style of metal roofs. How a metal roof looks impacts the aesthetics of the project but it goes way beyond that as well. There are peculiarities of each style of metal roof which must be considered. One of those things is that every metal roof has a minimum required pitch. Do not ever install a metal roof at a pitch lower than that recommended by its manufacturer! Sadly, I see this done all the time – people think they can beef up the underlayment or do this or that in order to get by at a lower than required pitch. Don’t do it! Even if the homeowner begs you and says “pretty please with a cherry on top” and promises they will never hold you liable. Don’t do it. Minimum pitch requirements are there for a reason. They are serious. Manufacturers would love to sell product for all roof types but, in some cases, it just doesn’t work. You can’t fool a raindrop! And, as for that homeowner who promises to never hold you liable? He or she will be the first one to hold you liable!
I do want to make a quick general statement before we dig into Profiles. Some of the profiles we will discuss are structural, meaning that they can be installed without solid decking beneath them. They can be installed over battens or purlins. Most of the profiles we will be digging into,, though, are architectural, meaning they must be installed with decking. This should go without saying but never install an architectural panel – pone of the panels that requires decking – without decking.
One more thing I will say, for residential applications, even if you are installing a structural metal roof, I really, really, really urge you to have solid decking as a part of the system. The problem is that, inside of homes as well as some other structures, we create a lot of moisture in of a relatively small space. We create moisture from cooking, doing laundry, taking showers, house plants – all kinds of things. That amount of moisture, even if the attic is vented per code, can still be enough to raise air humidity levels to the point where condensation occurs if the cold back side of the metal roofing is directly exposed to the warm, moist attic air. This is the risk with structural panels on homes. Again, my advice, never install a metal roof on a residence or other small, moisture containing building without having solid decking in place.
So, I want to break Metal Roofing Profiles down into two general categories and then we will take a look at the fifty thousand or so sub categories. Those two general categories are Vertical Seam and Modular Panels. Vertical seam panels only run vertically on the roof, and generally will not have any horizontal seams or laps. Modular panels on the other hand, usually have horizontal seams as well. And these are the panels that often are designed and fabricated to look like shake, shingle, slate, or tile.
Let’s look at Vertical Seam panel profiles first. I will break them down into sub-categories.
The first sub-category is Exposed Fastener. These panels are sold in a variety of profiles. Common profiles include 5V Crimp, R Panel, and PBR Panel. They are defined by their consistent vertically running corrugations. The fasteners used in them are typically screws with a rubber washer and a cap head. Because of the fact that they are direct screwed to the roof rather than a series of interlocking panels, these are extremely wind resistant products. The down side is that the exposed screws can have problems over time, such as the fasteners backing out, the washers cracking and failing, or the screw holes wallowing out or elongating, also causing the panels to loosen. This type of panel has no allowance vertically for the metal’s natural expansion and contraction with temperature changes. So, the impact of that movement is borne by the fasteners and the fastener holes. This will impact the roof’s wind resistance as it ages as screws can loosen or even break and the fastener holes wallow out. These panels usually are steel and are rarely made from aluminum because of aluminum’s higher expansion rate. The aesthetics of these products are sought after for certain jobs but are not real common on higher end homes.
I mentioned 5V as a common Exposed Fastener profile. That particular panel and its distinctive look is very much associated with coastal Florida and island areas. Really, the wind resistance of these sheets directly screwed to the roof versus other metal roofs with any sort of interlock speaks for itself. However, the lack of allowance for expansion and contraction is a negative for these panels, and jeopardizes wind resistance in the future. Additionally, because these are what I call “entry level” metal roofs, meaning they are on the low end of the scale as far as price, we end up seeing a lot of lower grade steels and coatings work their way into these panels. I also sometimes see secondary metal – metal that’s been rejected for quality purposes – finding its way into these panels. In that case, it’s important to understand metals and coatings so you know what you’re getting. Exposed Fastener panels also just have an overlap on their sides. So, they are not going to be as water resistant as some other panels with more aggressive interlocks panel to panel. Sometimes in these panels, though, butyl tape or butyl sealant will be used in the overlaps to enhance the water resistance.
There is also a hybrid version of these panels which are tile profile exposed fastened panels. These panels run vertically and have exposed fasteners but they also have horizontal steps pressed into the panels to simulate the look of clay tile courses. The horizontal steps actually serve a very beneficial purpose. They help to take up the metal’s expansion and contraction so that thermal movement is not borne entirely by the fasteners and fastener holes. Each course or step acts like a little accordion if you will, meaning these panels do not have the fastener problems that we see with panels that do not have these steps.
Now, contrasting with Exposed Fastener products, the rest of the vertical seam panel types we are about to cover have concealed fasteners.
First, let’s look at standing seam roof systems, and we’re going to break it down into two categories – snap lock and mechanically seamed. Snap lock panels are exactly what they sound like – the vertical seams snap together. There are actually two types of snap lock panels. One is traditional which consists of hidden clips to secure the panels to the roof deck. The other is called a nail hem panel. It’s called that even though it is usually applied with screws. When I describe this particular profile, the best thing I know to say is to think of vinyl siding that runs vertically up the roof instead of horizontally on a wall.
The hidden clip version of snap lock, when properly installed, has full allowance for expansion and contraction, making it ideal for roofs with long rafter lengths. Additionally, the clip helps support and provide additional wind resistance to the seam itself.
The nail hem version, on the other hand, has slotted holes for the fasteners. It is critical that crews installing nail hem panels be properly trained in regards to driving in the screw fasteners. The screws must all go into the middle of the slots and they must not be torqued down so tightly as to prevent the expansion and contraction of the roofing panels. If the screws are not placed properly or if they are driven in too tightly, ripples, known as oilcanning, will be forced into the panels.
The clipped standing seam panels can usually be used down to 2:12 pitch while the nail hem panels usually require a 3:12 pitch. This determination is primarily a result of the height of the seams. The clip-fastened version can have sealant in the seams as well for extra protection. One thing to keep in mind in regards to any vertical seam panel with sealant in the seams – you’re going to have real problems if you ever try to take the panels apart. So, if there is any advance thought that a roof might ever have to be modified, perhaps to add onto or remodel the structure, you will later wish that it did not have sealant in the seams.
These types of standing seam are commonly available in both steel and aluminum. It is not unusual for them to be available with the high end PVDF finishes and also with the runner-up super polyester finishes. These panels are available with different seam heights though generally the clip fastened panels will have higher seams than the nail hem panels. Clipped panels will have seam heights typically from 1.25” to 2” and nail hem panels will have seam heights usually less than 1.25”. The height of the seam determines how much water each panel can handle before it floods out and water penetrates the lock. For this reason, again, clipped panels with their taller seams will be preferred for longer panel lengths and also for that scenario I mentioned earlier where a higher level roof may be dropping water into one or two panels of a lower roof.
The remaining type of clip fastened standing seam is a mechanically seamed standing seam. These metal roofs are designed for low pitch applications. When these pans are first installed on the roof, there is no lock to the seam. The pans are installed and secured using clips. Then a seaming machine is run down the length of the seam to create a watertight lock. In old days, rather than use a seaming machine, they would use crimping tools in order to crimp the seams shut by hand. Sometimes mechanically seamed panels will have sealant in the seams as well. This is the style of metal roof that is commonly installed on large commercial and industrial buildings. Mechanically seamed standing seams can often be used at roof pitches as low as 0.25: 12.
That covers the vertical seam panels. Let’s move on to modular panel metal roofing profiles.
Modular panels come in a variety of sizes and styles. Many but not all of them have concealed fasteners and many but not all of them have interlocks on all sides of the panels. We often see these panels used for residential applications. One thing about residential applications is that the homeowners typically care about longer term warranties. So, most manufacturers of these panels use higher end coatings and finishes rather than “budget grade” coatings. These allow them to offer more aggressive warranties.
Modular panels almost always require a minimum 3:12 roof pitch and, in a few cases, 4:12. Keep in mind that if you install a modular panel that has a 1” formed thickness at its downhill edge, and it’s a 12” high panel, then that panel is creating a negative 1:12 pitch all by itself. If you installed it on a 1:12 pitch roof, the panels are sitting flat on the roof deck – not a good way to get water off of the roof, is it?
One thing to keep in mind on modular panels is that they can take some extra care for walkability. The formed thickness lifts the metal up off of the roof deck and, whether the panel is steel, aluminum, or copper, that does mean some extra care must be taken when walking the roof in order to prevent causing visible damages. Generally, that extra care is in the form of walking on the areas of the panel which are closest to the roof deck.
If a homeowner has roof areas where they walk frequently, perhaps to wash dormer windows or put up Christmas lights or something, many of these panels have optional foam inserts that fill up the airspace with a high-density foam. That helps allow the panels to be walked on. Now, a couple of things to keep in mind. Some of these panels are heavily textured so that can help mask the appearance of minor indentations, far better, really, than what happens on many vertical seam panels where every indentation can be quite visible. Additionally, as is the case with all metal roofs and in contrast with most other roofing materials, these products will maintain their impact resistance and walkability as they age.
As I mentioned earlier, there are some different fastening and locking systems with these panels. Most modular panels do have concealed fasteners but a few have exposed fasteners. We see this primarily with some tile profiles and some of the older stone-coated steel systems designed to be installed over battens. Additionally, while most modular panels have interlocks on all sides, some have overlaps on the sides. I would caution you again to think about water flow. If a roof is designed such that water may flow or be pushed sideways across the roof as it flows down the roof, you do not want that water running into a side overlap between the metal roofing panels.
Let’s cover metals now. There is so much to be discussed here but we’re going to focus primarily on the differences that may make you want to use one metal rather than another metal on a particular project. But, I will still provide some basic details as well.
The steel used in roofing is typically either galvanized or Galvalume. Both of these metals have carbon steel at their core. They then have a corrosion-resistant metallic coating that has been applied to both sides of the steel to keep it from rusting. In the case of galvanized, that metallic coating is primarily zinc. In the case of Galvalume, that metallic coating is primarily aluminum.
For some folks, this raises a question of curiosity. We hear a great deal about the possibility of electrolysis or a galvanic action occurring when two different metals come in contact with each other. Why doesn’t this occur when we place, for example, a coating of aluminum on top of steel? The reason is that, in order for a galvanic reaction to occur, there must be a catalyst introduced. That catalyst is commonly a salt or water. As long as the aluminum completely covers the steel, no pin holes or scratches or wear marks, then a catalyst can’t be introduced between the two different metals and no galvanic reaction occurs. This is one reason why, with both galvanized and Galvalume steel, it is very critical that care be taken to not scratch the surface of the metal and to touch up any scratches that do occur.
There are different grades of both galvanized and galvalume steel. The grade is based upon the thickness of the corrosion resistant coating on top of the steel. G90 is a common grade of galvanized steel used in metal roofing. The 90 refers to the fact that 0.90 ounces of galvanization has been applied to every square foot of the metal. There are lower grades of galvanized steel being used including G60 which is common in the agricultural market. Please realize that, when you use a lower grade steel, you are shortening the expected life of the product.
In Galvalume, AZ 50 is a common grade for painted metal roofing. For Galvalume roofing that just has a clear acrylic coating on it, AZ 55, which has 10% more metallic coating for corrosion resistance, is common. One thing to keep in mind, when you hear about clear or acrylic coated galvalume, is that the clear coating has a life expectancy of less than 10 years before it will be washed away – probably more like 5 – 7 years. Once that occurs, it is only the aluminum coating that prevents the steel from rusting.
As a warning, if you encounter a steel roofing material and the price seems too good to be true, it probably is. It is either a lower grade steel, with a shorter life expectancy, or it is steel that has been rejected by another supplier and then re-sold as secondary metal. Sometimes that secondary metal can conveniently lose the “secondary” tag as it flows through producers and distributors.
Something to be aware of is the Metal Construction Association Certified Metal Roofing program. This is a program that some manufacturers have become a part of. Through this program, those manufacturers are able to certify that their raw material, and hence the metal roofs they form from that raw material, are of a certain quality level. They have QA procedures in place, for example, that allow them to track their raw material on every project back to its source, and ensure that secondary metal was not used. This program also looks at the coatings used on these products and is a great way for contractors to assure their customers of the quality of the product being sold to them. There is both a Standard and a Premium level of certification through the MCA program.
So, back to galvanized and Galvalume. Why would you want to use one product over the other? The aluminum used on Galvalume erodes away at a slower rate than does the zinc used on galvanized steel which is good. But, zinc has a better ability to self-heal any scratches as well as cut edges.
Think about this, both the factory cut edges and the field cut edges on any steel roof expose a bit of carbon steel. It is so critical that your installers always cut steel with a shearing action that leaves a sharp, crisp edge rather than with, say, a sawing action that leaves a jagged edge. You want as little of that raw carbon steel exposed as possible.
When it rains, zinc molecules from the exposed galvanization coating on the cut edge go into solution with hydrogen from the water. Those zinc molecules are then deposited on the raw edge of the steel, protecting it from further exposure to the elements. Something similar happens to minor scratches that occur as well in the surface of the steel.
However, whereas this is what zinc molecules do, aluminum does not do this. Therefore, in the Galvalume coating, there is some zinc to try to accomplish this cut edge protection. But, there is not as much zinc to do it as there is with galvanized steel.
So, again, Galvalume wears better ultimately but it doesn’t self-heal cut edges and scratches as well. Keep in mind that, as far as the ultimate wearability of the two metals, if they have a paint finish on them, that paint finish has to completely wear away before the metal itself is ever exposed and this becomes a potential issue. So, that means the most vulnerable spot is indeed the cut or factory edges of the metal.
Bottom line, if you’re in a highly abusive, harsh environment, or if you want a product that can survive without a paint finish, Galvalume is preferred. However, if you’re more concerned about cut edge protection, if you’re concerned about scratches on the metal, or if you’re concerned about doing a lot of forming of the metal which could potentially stretch the paint finish and expose the steel, galvanized is the better choice. Most vertical seam products that have minimal forming to the metal and minimal exposed cut edges, therefore, will be made from Galvalume. But, when you get into heavily formed modular steel panels such as shake and tile profiles where the metal is being stretched and contorted and where you have more cut edges because of the many smaller panels, galvanized is usually the metal of choice.
Aluminum is another metal option. It is more expensive than steel so it won’t reach the price point of a steel roof. It also inherently isn’t as strong as steel. In areas prone to real severe hail or extreme heavy snowloads and, in particular on buildings with snow loads that cascade from higher roofs onto lower roofs, steel can be a very good choice. But, aluminum can be more easily formed than steel, and it is completely rust resistant. So, we see aluminum as a great material for products that are more decorative and have a lot of forming done to the metal. Additionally, we see aluminum in harsh coastal environments or areas subject to severe acid rain, because it won’t rust. To help give strength and support to the final roof system, we will see aluminum panels sometimes having those foam backers installed beneath it that we discussed earlier. One thing we do not typically see is aluminum being used in unpainted form. Unpainted aluminum is very difficult to form because the top surface tends to get very grabby or sticky.
Next, there are some exotic metals available as roofing. Copper and zinc are the two most common. Both can make great roofs, though they do have higher price points than steel and aluminum. Copper is very good even in corrosive environments. As you know, it will change color over time, turning dark brown originally and then later developing the characteristic verdi gris green color. The green patina will cause run off streaks any place it touches, and actually the anti-microbial effect of copper (and zinc) ions may leave clean streaks on the roof. So, when you install a copper roof, you need to think about run-off control. For example, if you let copper run off into aluminum gutters, eventually the aluminum will sacrifice itself to the copper through galvanic action, and corrosion will occur. Also, if the copper runs across stone, stucco, etc., it will leave deposits of copper in the form of green streaks on that material. Some property owners may like that, and others may not. It is something that you as the roofing specifier must discuss with them before they make their roofing choice.
We are seeing more zinc being used as roofing. Very common in Europe for hundreds of years, zinc is not inexpensive but it can make a great roof. We’re seeing it specified a lot on public use and government buildings. One critical thing about zinc is that moisture trapped against the surface of the zinc is its enemy. So, commonly with zinc roofs, there is a spacer material used behind the roofing to promote drainage of any condensation or other trapped moisture. Even though it may seem like overkill to have this spacer, it is used because moisture trapped against the zinc will cause rapidly damaging corrosion to the zinc. Zinc producers will encourage these spacers even if a protective coating has been directly applied to the back side of the zinc itself.
Let’s move on now to the coatings that are typically on metal roofs. The attributes of the various finishes will strongly impact what finish you want on any particular job.
First, let’s talk about paint coatings. Wet paint consists of three basic things and dry paint consists of two basic things. The three components of wet paint start with the solvent – that is what makes it wet. Next are the pigments, often called the solids – that is what gives the paint its color. And finally, the resin – that is the “glue” if you will that holds the pigment in place and also holds it to the base metal. Dry paint, then, has just pigments and resin because the solvent – the wet stuff – has been evaporated out of it.
Various paint chemistries, therefore, are defined most easily by their pigment and by their resin -- the stuff that gives it color and the stuff that makes it all stick together.
So, if the two primary items are resin and pigment, there are two things that happen to the paint as it ages. One is that the resin breaks down. As the resin breaks down, the pigment starts to be exposed to more ultraviolet light and, worst case, the pigment starts to chalk. Did you ever run your hand down the aluminum siding on grandma’s house and get all that white stuff on your hand? That is because the resin has started to break down and, as a result, the pigment is being lost. So, you want a resin that resists breaking down, especially if you’re in a harsh weather environment with lots of sun because sun is very damaging on resin.
Next, you want pigments that do not change color quickly. Again, the resin helps protect the pigment but that will only take you so far. Pigments used in metal roof coatings today generally fall into two categories – ceramic pigments which are man-made, and organic pigments which come from nature. Believe it or not, this is one area where man has excelled over nature. The man-made pigments perform far better than the natural pigments.
The two most common paint systems being used in metal roofing today are polyesters and PVDF, which stands for polyvinylidenefluoride. Both of these coatings are applied when wet to the metal while it’s still in coil form through a process called roll coating or coil coating. So, yes, these products are painted before the fabrication work is done on the metal. In the roll coating process, done at speeds from 250 to 750 feet per minute depending upon the particular production line, the metal is cleaned first, followed by a chemical pre-treatment that prepares the metal surface to accept paint. A primer is then applied and baked on followed by the top coat – the color coat – which is also baked on. You have perhaps seen a few multi-colored coatings and those usually have a print coat on top of the color coat and often, for extra protection, a clear coat on top of that. Clear coats are also common on some of the higher end finishes including metallic colors. Clear coats do extend the life of the paint system through extra protection.
Let’s look in more detail at the polyester coatings first. Polyesters are named for the resin that is used in them. They have proven to be good over the years but eventually the resin does break down and chalking occurs. As this happens, the pigments are exposed to more ultraviolet light and so they begin to fade. The paint manufacturers have developed a higher grade of polyesters called super polyesters and basically what they have done with these is require them to use only ceramic, or man-made pigments. That boosts the performance considerably. In fact, some folks have made claims that, after five years of exposure, the performance of these coatings is not far off that of the highest grade of coatings, the PVDF coatings. However, weatherization studies taken out to year 10 and beyond do show a marked drop off in performance of even the super polyesters. As the resin breaks down, we start to see chalking and also color loss.
Now we come to PVDF coatings. The resin in these coatings is from the mineral fluorite which is a very hard translucent green stone. The mineral is ground up to powder consistency and, because it has thermoplastic properties, it can be used in coatings. There is nothing even on the horizon today that out-performs these paint resins for their ability to remain solid and resist wear and breaking down as they age. To control the quality of these coatings, only certain paint producers are licensed to buy and use the PVDF resin.
In order to use these resins, a paint producer must use only ceramic pigments – the man-made pigments. So, these coatings are ensured of both the best resin and the best pigments for the best performance. By the way, the vast majority of the ceramic pigments have now been tweaked to be “cool colors” – so that they reflect radiant heat even in darker colors. This is what allows these coatings to meet Energy Star standards.
So, which do you want when specifying a painted metal roof? Polyester coatings or PVDF? I have a personal clear preference and it is based upon the quality of the PVDF coatings. However, there is a price difference between the two. If you’re in a mild environment meaning moderate amounts of heat, sunshine, and rain, and the property owner is not calling for top performance and the best possible warranty, polyester coatings can fit the bill nicely. However, in most situations, the PVDF finishes are going to meet the needs of even very demanding climates and clients. The PVDF chemistry provides the slowest erosion rate and the best fade resistance. I want to add, too, if the project is calling for a specialty finish such as a very bright, vibrant, saturated color like a red or a blue, or if the coating is a metallic, there is no doubt that the PVDF coating is what you will want.
I will add here that we are starting to see some work being done in metal roofing with PVDF coatings in powder form rather than the wet-applied coatings we have been discussing. These powder finishes are applied electrostatically and baked on after the metal roofing has been formed. The powder coats allow for texture to be built up on the surface of the metal and they also can allow for the blending of multiple colors.
There is another type of metal roof coating that we see being used, primarily on modular shake, shingle, and tile, and that is what we call a stone coating. Stone coatings are similar to the aggregate stones used on asphalt and fiberglass shingles, except they have been applied to a steel base. Like the powder coatings I just mentioned, the metal is fabricated first, and then cleaned, an adhesive is applied, and then the stones are applied, followed by a clear acrylic overglaze. Stone coated steel products, for consumers, create a nice bridge from asphalt shingles to metal. They have a great look and can include blended colors.
I want to now touch on a couple of additional things and provide you with some resources for your ongoing research.
First, I touched on this earlier – flared gables. These are common on log homes as well as some California and chalet designs. The ridge of the roof is wider than the eave. This situation can be tricky for some metal roofs. So much water – and debris – flows into the gables as it runs down the roof that it overwhelms many typical gable trims. So, what you need for these applications is a special flared gable trim. Not all metal roof manufacturers offer this, so you need to know that before specifying a particular metal roof for a flared gable.
Next, let’s talk quickly about solar attachment. I have never seen a metal roof that could not have solar panels attached to it. However, many of them will require fasteners through the metal roof, very similar to what is done with asphalt shingles. The primary exception is clip fastened standing seam panels. For these systems, the brackets for the solar panels can be clamped to the raised seams, with no fasteners penetrating the metal panels. If someone knows they will add solar to their roof in the future, standing seam would be a great option, even if they choose to use standing seam only where the solar panels will be installed, and then perhaps use a more decorative metal shingle or something on the rest of the home.
Finally, I can’t say a ton about this because warranties vary greatly from manufacturer to manufacturer but it’s important to know what sort of warranty will meet your customer’s needs best. How long of a warranty? Prorated or non-prorated? Transferable or not? These are all great questions … make sure that you know the warranties of the products you are selling.
This article has covered a great deal. Here’s the bottom line, though … if you’re going to be selling and installing metal roofs, make sure that those salespeople or others in your company who are helping to select and specify metal roofs understand as much as possible about the various metal roof systems and why one is superior to another for certain applications. They need to be able to help select the best product design, metal, and coating for each and every application.
The good news is, there are resources available to help with this education. First, align yourself with a quality metal roof manufacturer or two and take advantage of any and all training they offer. Next, here are some trade associations and other things that may help you.
Residential Metal Roofing Executive Report is published twice a month and it is full of help in marketing, selling, and installing metal roofing. I write many of the articles for it. You can subscribe free online at www.executive-report.com.
Metal Construction Association has many great articles and links and technical papers available at metalconstruction.org.
Metal Roofing Alliance has great links to leading manufacturers, as well as good information on the benefits of metal roofing. The website is metalroofing.com
An event held each year in March now focuses just on residential metal roofing, bringing together contractors and speakers from across the country for inspiration, sharing of best practices, and networking. Called the Metal Roofing Summit, the website is www.metalroofingsummit.com
My company also does training for metal roofing contractors, both for sales and installation. You can find information on those opportunities at www.midyeartraining.com and www.Isaiahindustries.com. As you connect with other manufacturers, you will find that they offer training opportunities as well.
Finally, please do not hesitate to contact me. I am always happy to answer questions, or even get involved in helping you market and sell successful metal roofing projects. You can reach me through my website at asktoddmiller.com and you can email me at firstname.lastname@example.org.
Posted By Western States Roofing Contractors Association,
Monday, February 5, 2018
Updated: Monday, February 5, 2018
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By: Dan Cornwell
Dan Cornwell is the President and founding member of CC&L Roofing Company established in 1978 in Portland Oregon and the Principal of Cornwell Consulting Group established in 2007. He is a former president of WSRCA, current director and former president of the National Slate Association, a member of the Tile Roofing Institute’s technical committee and the Secretary of the Portland Chapter of the Roofing Consultants Institute. Mr. Cornwell has provided consulting services on over 300 Construction Defect Litigation Cases. He can be reached for questions or comments at email@example.com
Picture This: You are a roofing contractor in the foyer at your office and in the process of shaking hands with a client who has come in to sign a contract for a lucrative job; the door opens and some guy walks in and serves you with a summons. You have just been named in a construction defect law suit and you and your client are both taken aback!
Of course you knew nothing about this coming, no one gave you notice of some alleged failure of your work and possibly you performed the work on said project 6 to 10 years ago or in some cases even longer. Possibly you don’t even remember the job, and if you do it is likely that there were no indications or notifications of anything wrong with your work. No one called you to say it was leaking or requested warranty service. This does not seem like fair treatment so how could this possibly repeatedly happen to roofing contractors across the Western United States?
How It Started
The course that brought you here may have begun a year or more prior to you being named and it is possible and even likely that the roofing portion of the project had little or nothing to do with the initialization of the law suit you have just been named in.
Every construction defect case usually has one or possibly two main drivers or actual serious defects that get the case started. Possibly the property owners in wet climates noticed mushrooms growing out the trim on the corners of their windows or noticed mold on the interior, possibly settlement issues caused cracking, or decks began to sag from rot or condensation caused the roof sheathing to sag under foot? Any of these would initiate the building owner to call someone for repairs which brings the defects in the construction to light.
If it a is condominium project or homeowners association, it is possible that professional plaintiffs experts looking for business initiated contact with the association board informing them of what the experts consider the boards “due diligence responsibly as trustees to ensure there are no latent construction defects prior to the expiration of the statue of repose”.
Whether the property owners noticed irregularity’s in the construction and initiated the call for repairs eventually leading them to an attorney or whether they were contacted by phishing plaintiff’s experts looking for business who directed them to an attorney makes little difference. Everyone is familiar with the term ‘Ambulance Chasing Attorneys” and today we now have “Sawdust Chasing Attorneys” or those along with their experts who rely upon construction defect litigation for their livelihood.
Once the plaintiff’s experts are on the scene they don’t just look at the portions of the construction that may be failing. Rather they inspect and observe all the building components often working from boilerplate lists of defects they have on file. Commonly following an initial observation of the building, a preliminary report is provided to the owners stating that a litany of potential defects have been discovered and additional investigative openings need to be undertaken to determine the severity of the issues.
The preliminary report usually leads to a select contractor being retained to preform destructive testing who makes investigative openings at numerous cherry picked locations in the building envelope while the plaintiff’s experts photograph and document the findings. The defects discovered during the invasive openings may be the actual cause of failures in the building envelope or structure with obvious resultant damage present. However, many of the alleged deficiencies which end up listed in the Lawsuit Complaint are often just technical in nature.
Although these technical deficiencies may be performing and causing no damage to the building, these alleged defects either do not follow the manufactures instructions, industry standards, ASTM or even code requirements. Often these issues are related to items such as type of fasteners, or fastener placements not meeting specs, underlayment or weather resistive barriers not properly lapped with other components or flashings, improper sealant joints, undersized diverter flashings and so on.
These items all get listed on the complaint filed with the courts and often they are described in ambiguous terms that do not give the reader a clear description of what the actual issues consist of? Some examples of these statements are: Inadequate weather protection for exterior wall assemblies: Inadequate metal flashing provisions and dimensions: Improper water-restive barrier installation: Inadequate rough opening flexible flashing provisions: Inadequate rough opening air control provisions: Improper utility penetrations: and of course: Inadequate weather protection at roof assemblies and maybe, inadequate or undersized diverter flashings at roof/wall/eave interfaces.
The plaintiff’s experts who make these allegations may or may not possess construction related experience and backgrounds, some may, and others may have construction management degrees but no practical experience with the tools of the trade while others might have zero construction training or experience but got hired on to take photos and quickly worked their way up the status of “expert witness”. However do not underestimate plaintiff’s experts, they all study codes, manufactures instructions, and or course WSRCA and NRCA installation details or industry standards and are quick to point out any conditions that do not meet those accepted standards.
If you are fortunate the experts hired by plaintiffs on your project will be those who commonly provide services for both the defense of contractors and who also occasionally work for plaintiffs. This experienced type of expert usually has a good and realistic understanding of what is and is not causing problems for the building owners and as such their demands for repairs may be more realistic than those who only work the plaintiff’s side and often just call for full replacement of all components on the exterior of the building. It is not that the “plaintiff’s only” experts are evil; rather they see themselves as righteous protectors of property owners who have been damaged by ruthless contractors and may be overzealous in obtaining justice and of course as much settlement money as possible for their clients. Put differently, they generally are very good at making mountains out of mole hills.
All of the above occurrences transpired unbeknownst to you at the job site which you worked on at some point in the past, the evidence has been gathered, the cards have be stacked and you are guilty of performing work on said project (be it improper work or not) and are now being sued for committing that work.
Who Sues Who?
Commonly you are a subcontractor and in most instances you are being sued by the general contractor who built the project. General contractors commonly require sub-contractors to name them as additional insureds on their insurance policies and once the general contractor is sued by the plaintiffs / property owners they turn the matter over to their insurance carrier for defense of the claim. Their insurance carrier then subrogates the claim to the subcontractors who may or may not be the cause of the defects alleged to exist at the property.
Even if the GC does not believe your work is a fault, even if you have a great ongoing relationship with them and have completed numerous jobs for the GC and might even be close friends after years of doing business together, once the GC turns the claim into their carrier for defense it is out of their hands. Their insurance carrier is going to look to you and every other subcontractor who performed work on the project to pay for the claim. Conversely if you hired any sub-subcontractors to perform any work on the project your insurance will also subrogate the claim to them as well. Who is actually at fault will be sorted out later. Unfortunately you are generally considered “potentially guilty” until proven innocent.
The Right to Repair
Some states have passed right to repair bills for instance in California, CA Civil Code 917 and in Oregon, ORS 701 in an effort to allow those who performed the work to have an opportunity to make repairs prior to the initiation of the law suit. These were put in place with good intentions but in some cases can have an adverse effect for subcontractors. In order to name you in a lawsuit the suing party must provide you with the required “right to repair” notices. Sounds good, but the requirement means that whether your work is suspect as contributing to damages at the property or not, if they don’t send you the notice of right to repair then they can’t name you in the suit. In essence this ensures that they will send you the notice so you are in.
The notice you receive may also include some ambiguous wording such as:
“Please note that the investigations and conclusions are preliminary in nature. It is impossible to know the full extent of the construction defects and damage at the property without additional major destructive testing. In compliance with the statues of (your state) you are required to:
1. Send us a written response stating your intent to perform some or all the remediation.
2. An offer to pay a stated amount of compensation for some or all of the acknowledged defects and consequential damages.
3. Or a letter denying all responsibility for the defects at the property”
This wording puts you in the position of agreeing to either fix or pay for problems at the property which you do not know the extent of, and have no way of knowing the eventual cost of repairs, or even if your work is at fault at all? At this point you end up notifying your carrier that you are being sued and turn it over to them to defend.
The Ultimate Statute of Repose
The statute of repose varies in time in different states and can be thought of as similar to a statute of limitations (ask an attorney for the true definition) for construction defect claims.
Your states statutes may vary but in California and Oregon it is 10 years and in Washington it is 6 years from the date of substantial completion or the issuance of the certificate of occupancy. Basically this means that upon the expiration the statue of repose property owners can no longer bring construction defect law suits against contractors. However these limits have been trampled on in some cases and upon appeal have been extended by judges who apparently thought allowing a case to proceed after 13 or 14 years was the right thing to do.
In some instances the general contractor was brought into litigation at the very end of the statute and by the time you get a summons, a year or more has past beyond the expiration of the statute, but since the case was brought against the general contractor prior to the expiration, who you named additional insured, you are now in the case.
What Happens Once Named in a Construction Defect Litigation Lawsuit
Once you are named: First notify your insurance agent who will notify your insurance carrier. Second; hopefully you kept good records of the construction process including photographs of the work in progress. You will need to copy your entire job file and supply it to your carrier as your file may at some point be subpoenaed by others and your attorney will certainly need your file for your proper defense. Your file is now evidence and you should keep both paper copies (in case of computer crashes) and electronic copies on file. Records from plaintiff’s or general contractor’s files may be incomplete or missing years after completion and you may even be accused of completing work you did not perform. Your file may be your salvation in such occurrences.
Your carrier will likely send you a reservation of rights letter which basically says they are looking at the case and may or may not provide coverage. This is complex stuff based on the fine print you probably never read in your policy, but in general they are required to provide a defense for you but may limit their exposure in paying for remediation of the alleged defects. In short they are responsible for damages to the property resulting from your work, but they do not cover your work product. So if your work is found and proven to be deficient, improperly installed and requires replacement but no damages to the building resulted from your work, there is no coverage and you are on your own for the replacement costs.
Whereas if there are resultant damages to the building from the work you installed, leaks and rot instance, this will trigger coverage for replacement and repairs. No one wants to have their work found deficient, but finding damage as a result of your work is actually a good thing in some cases as it will trigger coverage by your policy.
You insurance company will hire an attorney to represent you in the case and your attorney will, with approval of the carrier, hire an expert to aid in your defense. You may have a say in selecting who your expert will be and you will want someone with experience and knowledge in roofing installations. A good expert on your team can often refute overly aggressive claims of negligence on your part made by plaintiff’s experts and provide the proper arguments for your attorney to use in your defense.
You will need to provide your expert and attorney with your knowledge of the work process and as the case proceeds on you will likely be deposed by other attorneys in the case. However once this is accomplished and you have an expert and attorney working on your behalf, do your best to give them the ball and let them run with it. Go out and make some money and live your life and forget about the case if you can, eating your guts out won’t change the outcome.
Lastly once you are in the case, begin to earmark and set aside funds for your deductible payments when the case eventually settles or resolves. If you have changed carriers since completion of the work and damages have allegedly been accruing since that time, you may have multiple carriers providing and sharing in the costs of your defense, if that is the case you will likely end up making deductible payments to each of those carriers.
Your expert will visit the site and observe your work in place, potentially there may be additional destructive testing by the defense parties to open additional areas not cherry picked by plaintiffs in an attempt to either prove that damage is either isolated to only a few areas or is not occurring at all. Following the site visits and any additional destructive testing, there will be experts meetings where the experts for all parties including the attorneys meet in a room to discuss the findings onsite. Generally attorneys are not allowed to offer opinions in experts meetings, but the experts are allowed as guided by a mediator to hash out what they believe are and are not problems with the building and upon whom the blame rests.
It is not uncommon to have disagreements and a variance of opinions between the plaintiff’s, subs and the general contractor in these meetings as to where fault lies and how significant damages really are. Defense experts may prepare an alternative scope or repairs targeting problem areas that minimize the overall scope of repairs recommended by the plaintiffs. Much of the fault as to who caused it and or why damage is or is not occurring can be cleared up during experts meetings even though the opinions expressed therein are protected as mediation communications and cannot be used in court.
The best possible outcome is that your expert will be able to show the mediator and other parties during the meeting that your work is perfect and not at fault whatsoever. This may lead to your dismissal from the case once the other parties see that it will be difficult to impossible to either extract settlement monies from your carrier or for them to prevail against you at trial.
Following the experts meetings which may be repeated with two to three follow up meetings after additional investigative openings are made, or when new information comes to light, the case moves on to mediation. Prior to reaching this point, your expert will have arrived at a conclusion of whether or not any of your work is at fault. If some of your work is deemed faulty or potentially shares in resultant damages to the property, then a speculation is made of how much of the damages may be related to sequencing of the construction, or can be attributed to other trades modifying your work after completion and who should share in the costs of repairs? The general contractor will often be assigned to pay a portion or percentage of any damages caused by their subcontractors for failure to properly supervise their work.
Your expert will advise your attorney of how much, if any, liability you face in this case and provide an approximate estimate of the repair costs to remediate these problems or what portion of settlement demands made by the general contractor or plaintiff’s you may share in. Your attorney will then advise the carrier of the potential exposure in best in worst case scenarios should the case proceed to trial. The carrier based upon the information provided by your expert and attorney will assess the position and potential for loss should a jury not find in your favor at trial and will allocate a maximum settlement amount to be paid to settle the case on your behalf.
Commonly the parties attending mediation in the case meet in separate private rooms in the same building. Demands for payment to reach settlements are made by the plaintiffs to general contractor, who in turn makes demands for payment to the subcontractors in an attempt to settle the case.
The mediator travels back and forth from one room to the next, meeting with all the parties involved in an attempt to cajole the plaintiffs to take less and or the defendants to pay more to try to settle the case. It is common for no neutral ground to be reached at the first mediation with each party feeling out the others so the mediation fails. Often it takes a second and sometimes a third mediation prior to settlement being reached with around 99% of construction defect cases eventually settling in mediation. A successful mediation can be described as a situation where everyone goes away angry due to either paying more than they wanted or receiving less.
The remaining 1% of cases head to trial where anything can happen. Often as not the defense wins at trial having a good argument and reason to be there to begin with, however trail is always a crapshoot and juries can deliver big verdicts for plaintiffs as well. This is why most cases settle during mediation due to the fear of the unknown verdict coupled with the high costs of defense to bring a matter to trial.
Avoiding Construction Defect Lawsuits
Unfortunately the only surefire way to ensure you are not named in a construction defect case is not to do the work to begin with. Not a good choice when you make your living installing roofs, but the truth is when everyone who touches a building gets named in the suit, sooner or later even if you installed the most perfect roof ever, the windows, wall cladding, trim, doors, or decks or other components may fail and you will be in the case.
There are clause’s you can add to your contracts that may cut your exposure time limit down to four years or less instead of the full statute of repose in your state which are a very good idea. However you should consult an attorney for proper advice in your state as to the wording. These may not be of much help when you are required to sign the general contractors contracts unless you can get your clause added to their language.
Short of that, avoiding mass production lowest bidder home owner association work which is a main target for construction defect suits will avoid the most probable exposure. If this is your bread and butter type of work then try to get the general contractor to provide a wrap policy with high enough coverage limits for everyone.
Basically just doing really good work will either help you avoid being named in a lawsuit or get you out once you are named. Education for the business owner and the entire crew is paramount, even if your grand pappy did it that way and you have been doing it that way for decades that does not mean it meets the manufactures requirements, specs or even code. I don’t have room to mention all the potential defects that one can be accused of here so I will say that belonging to associations like the WSRCA and attending seminars, reading technical bulletins, and studying written details, then implementing those practices into your installations is the best possible method of either staying clear of or being dismissed from a construction defect claim.
Virtually every roofing contractor I know including my own company has at some point in time assumed the role of a “plaintiff’s expert”, although not necessarily involving a lawsuit.
You get called out to a property for service where the original contractor is either no longer in business or will not return calls or the owner simply refuses to have them back. The roof is leaking, and you find some of the worst cut corner sloppy work imaginable which of course was performed by the lowest bidder. You have to tell the property owner that they got a really bad job and then what it will cost to fix it or completely replace it.
You have just assumed a role similar to what plaintiff’s experts do, conversely should this roof lead to a law suit some attorney and some other expert will be hired to provide a defense for the guy who did the cut corner work described above. Providing a defense for really bad work obviously will not be easy.
My point in summation is that construction defect claims are not going away anytime soon, but they may in some instances have raised the bar on the overall quality of construction now being built. Hopefully those who are the critics, the plaintiff’s experts and attorneys, along with those who provide defense of the contractors involved can rise to a level of looking at what is wrong and what is not instead of attempting to extract as much money as possible from every party involved regardless of the quality of work completed. Not every contractor’s work is prefect and where faulty work causes damages it needs to be fixed. Hopefully we can get to a point that when the contractors work is not the cause of damage, that those who are the accusers will agree and dismiss the allegations.
However there is money involved, so don’t hold your breath.
Posted By WSRCA,
Monday, November 27, 2017
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Courtesy of: Phil Dregger - PE, Technical Roof Services
Phil Dregger is a Professional Engineer, Registered Roof Consultant, Fellow of the Roof Consultants Institute, and President of DNG Group Companies - Technical Roof Services and Pacific Building Consultants – in Concord, California. Mr. Dregger has investigated, designed, and provided expert testimony involving roofing and waterproofing systems since 1984. Mr. Dregger has special expertise in code compliance; wind damage, roof drainage; and analysis of condensation problems.
Many factors contribute to excessive condensation in low slope membrane roof systems installed over wood decks with insulation below; high interior relative humidity (RH), high roof reflectance, and especially air intrusion. One contributor - the impact of warm humid air leaking out the ends of improperly terminated exhaust vents - is like the proverbial 500-lb gorilla. We are keenly aware he is in the “reroof” room with us but have done a pretty good job of ignoring him. When this big guy creates a problem, however, roof professionals are often asked to explain why they did not “correct” the improper exhaust vent termination conditions before installing new flashing assemblies over them.
This article will explain why complete discharge of exhaust air - especially gas combustion products - is so important, will review code requirements for termination of exhaust vents, identify tell-tale signs of existing condensation problems, and will offer ways to avoid exhaust vent-related condensation problems.
Although broken or disconnected exhaust vents can pose an even more serious problem, this article will focus on how improper termination of exhaust vents can contribute to excessive condensation in low-slope membrane roofs. All photos in this article are courtesy of DNG Group Companies - Technical Roof Services and Pacific Building Consultants - and show projects located in California in ASHRAE Climate Zone 3.
Soft Spots – Serious condensation problems usually start with someone noticing a soft spot like that shown in Figure 1. Usually, the soft spot is positioned near a “high” point on the roof, usually the roof construction contains air spaces with cold surfaces, usually the reroof membrane is considerably more reflective than the old roof membrane, and more often than not the roof is installed over a residential occupancy.
Before we go further, let’s review some condensation related concepts: relative humidity, dew point, radiative cooling, and convective air currents.
Dew Point and Relative Humidity (RH) – Let’s say it is 52°F outside and foggy. The air can’t hold any more water vapor. It is at its dew point temperature. It is at 100% RH. The water vapor present starts condensing on exposed surfaces. Since warm air can hold more water vapor than cold air, if we let this air inside and heat it up to 72°F, its RH drops to 50% but the dew point temperature doesn’t change. So, if we cool down the air back down to 52°F (the dew point temperature), condensation of water on surfaces will begin again. Pretty straight forward. Condensation is primarily related to the temperature of the air and the surfaces it encounters.
What we need to keep in mind is that on most winter nights the temperature of our wood roof decks, when we insulate below the deck, gets well below the dew point temperature of the air inside our buildings even here in sunny California. This means that if the air inside our buildings were to come into contact with our wood decks at night, it would condense. It does and it does. I’ll explain why.
Smoke and Dew - Two things we learned as kids. Smoke rises and dew forms on grass overnight. Later someone explained to us this was because warm air is less dense than cool air (thermal buoyancy) and surfaces exposed to a clear sky at night lose lots of heat (radiative cooling). This means that the air inside our buildings naturally wants to rise up into our roof assemblies. And, if it’s cold outside - and especially if the sky was clear overnight - the intruding air will cool down to its dew point temperature and condense inside our roofs.
This happens all the time and usually our roofs have enough water storage capacity that it doesn’t create a problem. But sometimes too much water ends up condensing and things we don’t like to talk about start to grow, and wood starts to decay. At the moment, I’m referring to condensation of water vapor that hitched a ride up into the roof on a convective air current. It can get a whole lot worse if the air we’re talking about condensing is being propelled under pressure out the end of an improperly terminated bathroom fan duct or gas flue vent.
There are two basic kinds of exhaust vents: environmental air ducts and gas vents. Living units (single family homes or multi-unit apartment buildings) typically have two or three exhaust vents per unit; something like 1 or 2 every 1000 sf of roof area. Roofs over most non-residential occupancies have far fewer exhaust vents. Figure 2 shows a high concentration of exhaust vents on the roof of a three-story apartment building.
Environmental Air Ducts - Environmental air ducts are typically single walled, do not have any required clearances from combustible materials, and are connected to exhaust fans serving bathrooms, stove hoods, and/or clothes dryers. The exhaust air is “pushed” along by a fan.
Gas Vents – Gas vents are typically dual-walled, require minimum clearances from combustible materials (because they can get hot), and are connected to appliances like gas water heaters and gas furnaces. By the way, when gas is burned it produces heat, CO2, and lots of water vapor. This is why you sometimes see water dripping our of a car’s exhaust pipe. Water heaters typically rely on convective currents to carry the combustion products up and out of the gas vent. Furnaces typically have “draft” fans to help push the combustion products up and out of the gas vent.
If the gas combustion products are completely vented to the outside, great. If not, you can get serious condensation and wood decay. Figure 3a shows a “soft spot” (red arrow) found next to an improperly terminated gas vent. Figure 3b shows the gas vent improperly terminated inside the roof flashing assembly very near deck level.
You might ask, “How, then, are exhaust vents supposed to be terminated?” Good question. It depends on the type of exhaust vent you’re asking about. Code requirements for environmental air ducts and gas vents are different.
Code Requirements – The 2013 California Mechanical Code (CMC), based on the 2012 Uniform Mechanical Code , Chapters 5 and 6, requires environmental air ducts, including joints, to be substantially airtight and terminate outside the building at least three feet from openings into the building. Note: The 2013 California Residential Code refers back to the CMC for requirements.
The conditions shown in Figures 4, 5, and 6 were all discovered while investigating “soft spots” on reroof projects. Figures 4a and 4b show a “wet” cover board next to 7” air ducts which terminate below 5” T-top flashings. Figures 5a and 5b show two air ducts positioned in one oversized deck opening and terminated inside one large roof flashing. Figures 6a and 6b (red arrows) show a rectangular air duct stopping at deck level and then “extended” upward using a round roof flashing.
It is not clear if the metal flashings installed over these air ducts would be considered extensions of the duct or not; or if the openings in the decks around the ducts would be considered “openings into the building”. Nevertheless, these duct terminations and flashing conditions were all strongly suspected to allow some portion of the exhaust air to flow back into the insulated rafter spaces and make a major contribution to the excessive condensation conditions present.
Gas vents have different termination requirements. The 2013 CMC, Chapter 8, requires gas vents to extend completely through roof flashings, extend to a height at least 12-inches above the roof deck, and have “listed caps”.
Figure 7 shows two properly extended and terminated gas vents.
Know Your Codes – Codes address other aspects of roof construction that potentially impact how much water accumulates in a roof assembly. I’ll mention just two:
· The 2013 California Energy Code (CEC), Section 110.7, requires sealing of joints, openings, and other potential sources of air leakage into or out of the building envelope.
· The 2013 California Building Code (CBC), based on the 2012 International Building Code, Section 1203, requires cross ventilation of “enclosed rafter spaces”.
Code provisions are amended and/or interpreted on the local level; sometimes quite differently. Accordingly, I suggest roof professional review local code amendments and/or seek clarification with the local code official regarding how various code provisions apply, or don’t apply, to specific reroofing projects.
Compact Roofs and Framed Roofs - Borrowing terms coined by Wayne Tobiasson of the Cold Regions Research and Engineering Lab (CRREL), I refer to the roofs with rigid board insulation above the deck as “compact” roofs and those with batt insulation below the deck, as “framed” roofs[i]. Some roofs have or end up having insulation above and below the deck. I call these roofs “a good idea”.
West Coast wood framed roofs with only batt insulation below the deck are inherently prone to condensation. They are prone to condensation because they contain air spaces with cold surfaces. And, usually, the air inside the building has a pretty easy time working its way up into these air spaces and condensing. Compact roofs, on the other hand, have limited air spaces with cold surfaces (e.g., joints of insulation boards) and by their very construction naturally resist air intrusion. We’ve talked about this before. 
Blindsided – The most common cause of a serious condensation problem (e.g., soft spots) is, well, an existing condensation problem. This is true regardless if the existing problem is due to intrusion of high RH air or leaky exhaust vents. In such cases, if highly solar absorptive roofs are replaced with highly reflective roofs, roof professional can inadvertently kick into high gear existing condensation problems; and end up wondering what hit them. Note: The same physics apply when a “cool” coating is applied over a “non-cool” roof membrane.
Many older low slope membrane roofs installed over wood decks with insulation below have condensation problems; they accumulate more water than they should. Usually, however, they also have roofs that absorb lots of solar radiation. The highly absorptive (non-highly reflective) roofs get hot whenever the sun comes out and work to rapidly dry accumulated water downward. This can keep even fairly serious condensation problems at bay for years. When these roofs get replaced after 13 to 18 years, they often require replacement of an unusually large amount of deck; enough to make a roof professional wonder why the owner didn’t complain more about roof leaks.
Keep this in mind. A large amount of deteriorated wood decking without a corresponding high number of reported leaks, is a telltale sign of an existing condensation problem.
Unfortunately, when an existing condensation problem is unleashed by installation of a “cool” roof, wood decks can starting showing nasty bite marks (e.g., soft spots) after just a few years. This was sort of an epiphany to me; and maybe to you too.
As mentioned above, the silver lining to this ominous cloud is that existing condensation problems usually exhibit telltale signs - if you know how to read them.
Warning Signs – The best time to find out a roof has an existing condensation problem is before the roof is specified and bid. However, the best time to see warning signs is during roof removal.
Before tear-off warning signs include reports of roof leaks when it is not raining, soft spots not near penetrations or flashings, ceiling stains near high points, and multiple stains below metal hangers.
During tear-off warning signs include more decay than the number of reported leaks suggest, decay at locations not readily explained by roof leaks, and exhaust vents that terminate very near the roof deck.
Figure 8 shows an area of concentrated decay. The area is not near a low spot or next to a penetration but penetrations are nearby. No rain leaks were reported and the top of the gypsum ceiling boards had only limited stains. The decay is not reasonably explained by a roof leak – it is a telltale sign of an existing condensation problem.
Low Exhaust Vents - When “low” exhaust vents are uncovered, extend them in accordance with code requirements. Obtain the assistance of a mechanical engineer or a design/build mechanical contractor as needed. Figures 9a and 9b show one example of how existing low air ducts can be extended and flashed.
Summary - The best way to deal with a 500-lb gorilla is to swing open its cage and face it head on. Keep in mind improperly terminated exhaust vents can discharge large amounts of water vapor into enclosed rafter spaces and that some roofs rely on solar heating to keep excessive condensation in check. Extend and flash low exhaust vents, as needed, in compliance with local code requirements. Watch for telltale signs of existing condensation problems, especially if your project involves replacing a highly solar absorptive roof with a highly solar reflective one.
If unusually large amounts of decking need to be replaced and the large amounts can’t be reasonably explained by roof leaks, investigate the cause; it is likely due to the intrusion of high RH interior air and/or leaky exhaust vents. Depending on the results of the investigations, air sealing around penetrations, adding rigid board insulation above the roof deck [i] [ii], repairing exhaust vents, and/or upgrading mechanical ventilation systems inside may be warranted.
Note: The 2013 CEC, Section 150, based on ASHRAE Standard 62.2-2010, now requires mechanical ventilation for all low-rise residential buildings for indoor air quality which also really helps to control interior RH levels.
 P. Dregger, "Cool Roofs Cause Condensation — Fact or Fiction?" P. Dregger, Western Roofing, Jan/Feb 2012.
 P. Dregger, "Air Infiltration: The Enemy of Wind Resistance and Condensation Control," RCI Interface, June 2002.
 W. Tobiasson, “Roofs”, ASTM Manual 18 2nd Edition, January 2009
 A. Desjarlais, et al, “Hygrothermal Performance of West Coast Wood Deck Roofing System”, Nov 2013, Pub 47188.
 P. Dregger, “Good But Potentially Misleading Guidelines”, RCI Interface, May/June 2014.
Posted By WSRCA,
Wednesday, November 8, 2017
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Greetings to Members of Western States Roofing Contractors Association:
Steep‐slope roofing safety requirements and regulations continue to evolve and have become more stringent in an effort to provide safe working conditions. Agencies such as the Occupational Safety and Health Administration (OSHA) strive to regulate exposure to hazards through the development of workplace health and safety standards. Steep‐slope roof environments can pose numerous challenges and work on steep‐slope roofs has become more and more scrutinized as governmental regulations have been tightened.
Our roofing industry is well aware of the challenges with maintaining safe working environments, and in our on‐going work with WSRCA’s Self‐Adhering Underlayment Slip‐Resistance Research and Testing Project, we have performed slip‐resistance testing of numerous steep‐slope roofing underlayments. This research and testing project was initiated in response to ASTM’s removal of slip resistance criteria from ASTM D 1970, the standard for Self‐Adhering Polymer Modified Bituminous Sheet Materials Used as
Steep Roofing Underlayment for Ice Dam Protection.
WSRCA’s Steep, Industry Issues, and Safety Committees’ preliminary test data confirms, in our opinion, that the value and importance of this testing project, with the goal of reintroducing slip‐resistance criteria back into ASTM D‐1970 Standard, as well as other underlayment material standards, simply is a matter of worker safety. WSRCA’s slip‐resistance testing has been conducted using a British Pendulum Tester, following the procedures outlined in ASTM E303‐2008 Standard Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester, which appears to be a very suitable test method.
To date, we have tested ten (10) commonly used and widely distributed roofing underlayment materials available in the Western U.S. market. Each underlayment was tested both dry and wet per the ASTM E303 test protocol. Table No. 1 below provides initial test data and is intended to provide a basis of comparison of general slip resistance for various commonly used roofing underlayment materials. Because the slip‐resistance test measures friction, the higher readings indicate a more slip‐resistant underlayment surface and low readings indicate a less slip‐resistant (i.e., more slippery) surface.
WSRCA’s Steep‐Slope Roofing Committee believes that all roofing underlayment products, including ice‐dam protection membrane underlayments, should have a required series of select physical properties to be tested and/or rated, and published in manufacturers’ Product Data Sheets, including slip‐resistance, similar to other characteristics that are already standard underlayment tests, such as:
o Tensile Tear – tested per ASTM D4073 – Standard Test Method for Tensile‐Tear Strength of Bituminous Roofing Membranes.
o Cold Bend – tested per ASTM D2136 – Standard Test Method for Coated Fabrics—Low‐Temperature Bend Test.
o Permeability – tested per ASTM E96 / E96M – Standard Test Methods for Water Vapor Transmission of Materials.
o Shower Test – tested per ASTM D4869 / D4869M – Standard Specification for Asphalt‐Saturated Organic Felt Underlayment Used in Steep Slope Roofing.
o Dimensional Stability – tested per ASTM D4869 / D4869M – Standard Specification for Asphalt‐Saturated Organic Felt Underlayment Used in Steep Slope Roofing.
Initial Slip‐Resistance Testing Results:
Concerned with the removal of slip‐resistance criteria from ASTM D 1970 Self‐Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection, WSRCA has embarked on this Slip‐Resistance Testing and Research Project with the desire to have the industry participate and assist with the development of updated ASTM roofing underlayment standards. Table No.1 below documents WSRCA’s preliminary slip‐resistance testing data of commonly used and commercially‐available steep‐slope roofing underlayments. Please be aware that the ASTM E303‐2008 testing protocol states that the first test result from the pendulum swing is not recorded, as indicated in Table’s testing data below.
WSRCA Recommendations and Summary:
With the importance of safety in mind, WSRCA encourages manufacturers of steep‐slope roofing underlayments to conduct slip‐resistant testing of their products and provide the test data/information to the Industry in their product data sheets, in effort to work with associations such as WSRCA to incorporate slip resistance into ASTM roofing underlayment standards as one of the physical property attributes that are tested and measured. It is with this WSRCA research, pro‐active testing work, and solid data that WSRCA representatives intend to lobby ASTM Underlayment Task Groups and the D08.02 Sub‐Committee to incorporate slip‐resistance criteria into all roofing underlayment material standards.
Thank you for your participation in the western roofing industry and for counting on WSRCA to provide our Members with industry‐leading technical work, and member assistance, for use on your roofing and reroofing projects. WSRCA endeavors to promote quality and help maintain safe work environments.
Thank you for continuing your membership to support Western States Roofing Contractors Association in our active efforts with research and testing to strengthen and advance technology and science into the art of roofing.
Posted By Chris Alberts, Western States Roofing Contractors Association,
Wednesday, November 8, 2017
Updated: Wednesday, November 8, 2017
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Greetings to Members of Western States Roofing Contractors Association:
Changes in materials and methods used to produce rigid polyisocyanurate insulation boards for roof systems has been a concern for WSRCA members at different times over the years. As you may recall, WSRCA’s Low‐Slope Committee provided WSRCA Members with a Technical Bulletin in 2000 a follow‐up during 2004 (No. 2004‐1) about changes in blowing agents and the LTTR (i.e., published results of long‐term thermal performance testing) regarding R‐values per varying thicknesses of polyisocyanurate insulation. It appears that as the manufacturers continue to fine‐tune the polyisocyanurate insulation manufacturing process in order to comply with regulations, while still producing quality products with the necessary properties, issues are occurring and being observed in the field, of which our members should be made aware. The issues may require new action(s) by the industry. Reports from the field indicate that longitudinal depressions (e.g., also referred to as ruts or grooves) appear to be occurring with more regularity in rigid polyisocyanurate foam insulation boards delivered to job sites and some are being used in roofing systems. This issue that had previously only been seen infrequently, appears to be becoming common.
The ruts or grooves observed are associated with “knit‐lines,” which are lines formed during manufacturing when the flow of liquid‐state expanding foam from multiple mix heads meet as the material expands just down the manufacturing line from the liquid‐chemical outflow points. As two neighboring lines of expanding liquid foam material meet, if a slight amount of skinning‐over has already taken place, and the two masses of foam do not completely meld homogeneously, it leaves a visible line in the material. The two sides, under most ordinary manufacturing conditions, can bond together but there may be a readily‐visible line of compressed polyisocyanurate cells across the thickness of the board and these are called knit‐lines.
In the rigid roof insulation materials that are presenting issues, there are varying sizes of grooves or depressions in the facers of the foam boards along the knit‐lines, running the length of the board, as if there was not enough foam insulation material and/or foam expansion to fully fill in and contact the facer along where the depressions occur. As these affected boards are installed end‐to‐end on a roof, the grooves or ruts may align and extend across the roof. Depending on how the insulation boards are installed relative to the slope of the roof, the ruts may run perpendicular to the slope and can inhibit drainage. However, of greater concern is the possibility that the board’s facer could be unadhered and may also be bridging across these knit‐line depressions. In a fully‐adhered single‐ply roof membrane system that is applied directly to the facer of polyisocyanurate insulation boards, there appears to be a potential for wind‐uplift issue(s) and/or damage as a result of the voids under the unbonded facer.
We note that this issue is being discussed at the National Roofing Contractors Association (NRCA) as well. An article written by Mark Graham, of NRCA’s Technical Section, regarding testing of rigid polyisocyanurate insulation board used in roofing, published recently in NRCA’s Professional Roofing Magazine, (Professional Roofing 12/02/2016, Another Round of Polyiso Tests, by Mark Graham.) touches on this subject. In the article, Mr. Graham states,
“…the issue of surface depressions associated with knit‐lines in faced, rigid board polyisocyanurate insulation is of particular concern. Although this problem was previously seen only in isolated instances, it now appears to be more pronounced and widespread with the current generation of polyisocyanurate insulation blowing agents and manufacturing processes. Polyisocyanurate insulation manufacturers need to improve the flatness of their roofing‐specific products, and appropriate evaluation criteria need to be developed and included in Faced Rigid Cellular Polyisocyanurate Thermal Insulation.”
As was stated in WSRCA Technical Bulletin No. 2014‐02 (“Updated Results of Long‐Term Thermal Resistance [LTTR] Testing, and R‐Value of Current Generation Polyisocyanurate Roofing Insulation”), over the past few decades the manufacturing of plastic foam roof insulations has undergone numerous changes, partly due to tightening regulations and governmental mandates to lower the amount of ozone‐depleting gases and VOC‐related blowing agents released into the atmosphere. Blowing agents evolved from the use of chlorofluorocarbon (e.g., CFC‐11) in the 1980s, to less volatile hydrochlorofluorocarbons (e.g., HCFC‐141b) with reduced ozone depletion potential and a lower global warming index in the 1990s, then changing again to pentane and cyclopentanes in the early 2000s.
Those earlier changes, and continued refinement of blowing agents, have caused manufacturers to invest significant assets in order to maintain producing successful polyisocyanurate roof insulations. Polyisocyanurate has been the most widely used rigid foam board in U.S. roofing assemblies for decades due to its high R‐value, fire resistance, and relatively low cost. Problems with dimensional stability had occurred over the years especially as manufacturer’s responded to regulations regarding potentially ozone layer‐harming chemicals used in blowing agents, and changed formulas. But over all, it has continued to be the most regularly specified rigid insulation board in low‐slope membrane roofing systems. Irregularities associated with the knit‐lines were reported occasionally in the past, but WSRCA Member reports are becoming more and more frequent and more concerning to WSRCA’s Low‐Slope and Industry Issues Committees. We have heard that some of the manufacturers have purportedly addressed this issue as merely an aesthetic one, but WSRCA, and other roofing industry organizations are concerned that this is a technical issue with potential for resultant roof problems.
Lack of Full Facer Adhesion:
When polyisocyanurate foam’s knit‐line grooves are deep enough and have left the facer unadhered along the length of the knit‐lines, the result is the same as facer separation, which can be a significant problem. Even though the knit‐lines result in the facer being unbonded at intermittently spaced portions of the board, across the surface of each insulation board, a relatively significant percentage of the surface area of the facer does not provide adequate wind‐uplift resistance for adhered systems. When we stop and think about this item or issue, it may be a problem over the life of any particular adhered roof system. Not all of our Member contractors, designers, and even some of our membrane manufacturer representatives may realize the potential magnitude of the emerging issue.
Variation in Board Thickness:
Judging by some of the photos being sent in by our WSRCA Members, and from what we have seen in the field on projects this year, polyisocyanurate roof insulation affected by visibly‐apparent knit‐lines can also result in a variation in board thickness, which can have another set of potential problems. One of these issues is continuous R‐value: Insulation R‐value averaging was once allowed by the Code. However, as you may be aware, most code jurisdictions no longer allow R‐value averaging, and now they require Total R‐value throughout the entire roof area. If the current polyisocyanurate insulation (i.e., which is knit‐line affected) varies in thickness, which some of the photos herein from WSRCA Members clearly show, then the Total R‐value of the roof system may be placed in question or jeopardy from a strict code violation perspective. And, if any of our Member contractors are having to guarantee the roof’s R‐value, which occasionally is required for sensitive projects, the Total R‐value over the full roof area may be affected by insulation that is compromised by knit‐lines with significant depressions along each of the insulation boards.
Potential for Condensation Issues:
In a mechanically‐fastened roof system with multiple layers of insulation board and potentially a cover board, where no vapor retarder is installed, the grooves in the boards create open pathways for air movement. In winter time heating climates, if there are any air leaks from the interior of the building, these pathways could help convey warm, moistureladen air through‐out a roof area and potentially form liquid water on the cold underside of the membrane from condensation, especially in our colder climate regions.
Problems at Membrane Lap Seam and Transitions at Boots:
Forcing a roof membrane to conform with an irregular substrate may be problematic at laps and seams in the membrane. The relatively deep grooves we are seeing in some insulation boards could increase the likelihood of voids and fishmouths at lap seams, boots, and patches, which could result in openings, the potential for moisture entry, and/or leaks.
Summary of Potential Issues:
Unbonded Facer: Issues with the knit‐lines could be potentially problematic for wind‐uplift resistance where roof membranes are adhered directly to polyisocyanurate insulation boards if the facer is partially unbonded or has disbonded and delaminated from wind and/or thermal cycling movement along grooves or ruts at the knitlines.
Affected Adhesion: These irregularities may also interfere with proper adhesion between layers of insulation boards or coverboard in a roof assembly.
Effect on R‐value: Less of a concern, but still relevant is the possible effect on R‐value caused by changes in thickness along the knit‐lines. Especially if the roofing contractor is being required to guarantee R‐value of an installed roof system.
Air and Moisture Pathways: In a mechanically‐fastened system, grooves or ruts in both faces of rigid insulation board could provide pathways for air leakage from the building interior that may result in condensation within the roof assembly.
Drainage Interference: Grooves that run laterally across a roof that telegraph through the membrane can interfere with roof runoff and drainage.
Voids in Fully‐adhered Systems: Where roof membranes are to be fully adhered directly to facedpolyisocyanurate insulation boards, grooves in the insulation surface that intersect membrane laps can create difficulty in achieving a fully adhered seam, creating the potential for voids, fishmouths, and consequent moisture entry or leaks.
Purpose of Bulletin:
The irregularities that WSRCA is cautioning the western roofing‐industry about in this bulletin appear to be occurring with significant frequency throughout the Western States region. Because of the potential for these issues to become significant problems, which could result in wind‐related failures, reduced R‐value, standing water, debris accumulation, dark staining, increased membrane heat aging, and potential leaks, WSRCA desires all our members be aware of the issue. WSRCA encourages its members to be on the lookout and thereby try to prevent potential for problems on their projects before they occur. In addition, we want to encourage the manufacturing sector of our industry to take this issue seriously, and not as just an aesthetic problem, and to find ways to eliminate or address the problem of knit‐line irregularities and lack of facer adhesion.
As a result of continuing reported issues, WSRCA would like to update and restate our prior recommendations. In order to alleviate potential problems, WSRCA and its Industry Issues and Low‐Slope Committees continue to recommend the use of properly selected coverboard(s), appropriate for the climate and job’s conditions, and the type of roof system being installed, as a vital component in the successful design and construction of durable, long‐term, fire‐and hailresistant low‐slope roof assemblies. The use of a rigid coverboard over insulation that may have minor irregularities in the surface may help to minimize some of the potential problems those irregularities could cause.
1. Where possible and feasible, check the condition of polyisocyanurate insulation boards prior to accepting delivery and before installing them in a roofing project.
2. Educate supervising employees regarding the potential for compromised insulation boards and/or their unbonded facer(s).
3. Where possible on adhered roof assemblies, until all knit‐line affected insulation becomes a thing of the past, consider bead size and bead spacing of low‐rise foam and/or hot asphalt to attempt to more thoroughly adhere insulation and coverboards. Please note that WSRCA Low‐slope Committee intends to release a companion bulletin regarding lowrise foam insulation and coverboard adhesives in the near future.
4. Where possible and feasible, utilize coverboards rather than directly applying roof membranes to polyisocyanurate insulation boards.
5. Please continue to inform WSRCA regarding problems encountered in any of your roofing and waterproofing projects, and when possible provide photos as well.
Thank you for your support of Western States Roofing Contractors Association, and our active efforts to strengthen and advance technology and science in our industry, as well as to promote the art of roofing and waterproofing. We trust this information aids you to promote quality roof systems capable of long‐term successful performance.
Posted By WSRCA,
Wednesday, November 8, 2017
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Greetings to Members of Western States Roofing Contractors Association:
Over the last several years many of our WSRCA members have become more aware of the flooding hazards associated with low‐lying coastal areas and near river valleys where flooding may have historically occurred, and in certain areas that seem to flood with some regularity. However, recent climate events reportedly have caused many unexpected and “flash‐flood” events, even in areas otherwise known to the layperson as desert areas, which have caused millions of dollars of damage to nonwaterproofed buildings. Some of these flood events have occurred in fairly large metropolitan areas and some in densely populated urban areas of the U.S.
The Federal Emergency Management Agency (FEMA) has long been involved with regulating how buildings located in flood‐prone areas should be constructed, or repaired, and/or retrofitted. However, recently Factory Mutual (FM) published a new Factory Mutual Global Property Loss Prevention Data Sheet 1‐40 regarding floods, partial‐building waterproofing, etc. Some WSRCA members may be aware of FM’s 1‐40 published during 2016, but FEMA’s regulations and guidelines for Special Flood Hazard Areas (SFHA) may be less familiar to some of WSRCA’s members involved in aspects of waterproofing. This bulletin is intended to impart additional waterproofing and “flood‐proofing” information to WSRCA Members.
FEMA’s Special Flood Hazard Areas are locations that may not have regular flooding but are subject to significant flash flood events on a much less regular basis, and are associated with what are referred to as 50‐year, 100‐year, or 500‐year storm events.
When the quantity of flood water is primarily made‐up of rain water, as opposed to snow‐melt or other contributors, one of the main factors designers must consider is rainfall intensity. Rainfall intensity is typically expressed as inches of rain over a given time frame, and the U.S. Weather Bureau maintains rainfall records for the United States and most major cities in any particular state. The specific rainfall data is regularly updated by the National Oceanic and Atmospheric Administration (NOAA). The chance that an unusually heavy or intense rain may reoccur is referred to as a “reoccurrence interval” and is sometimes stated as a 50‐year or 100‐year chance of reoccurrence. The Table below provides examples of a 100‐year reoccurrence interval for several Western States and select cities in these listed states.
One such FEMA guideline document that provides detailed information on this Federal agency’s recommendations and requirements for residential construction and retrofit work, which can help WSRCA waterproofing professionals working in a SFHA is: Engineering Principles and Practices for retrofitting Flood‐Prone Residential Structures (Third Edition) FEMA P‐259 / January 2012. While the document is provided primarily for the design professional’s use, it is also helpful for the waterproofing contractor that may get involved in a retrofit or a new construction project in a location designated by FEMA as an SFHA, as our WSRCA members endeavor to understand the requirements outlined in these relatively new documents. A full copy of this FEMA document is available for download at https://www.fema.gov/medialibrary/assets/documents/3001.
The requirements, outlined in the aforementioned document, for making changes or repairing buildings within these flood hazard zones are multi‐faceted. These requirements may impact waterproofing contractors who are asked to make an existing building either permanently or temporarily flood resistant. Permanent flood resistance is referred to by FEMA as “Dry Floodproofing” and is defined as: “Strengthening of existing foundations, floors, and walls to withstand flood forces while also making the structure watertight.” Temporary flood resistance is referred to as “Wet Floodproofing” and is defined as: “Making utilities, structural components, and contents flood‐ and waterresistant during periods of flooding within the structure.”
FEMA has strict requirements for new construction that must be met if a new building is to be located within a SFHA. These requirements must also be followed for existing buildings located in a SFHA that undergo substantial improvement or that are substantially damaged buildings undergoing repairs and waterproofing or dry floodproofing. These requirements can impact the contractor’s work in a variety of ways, but the important thing to be aware of is that there are special requirements and it is important for those involved in construction or repairs to be apprised of the requirements.
Whether your waterproofing project is commercial or residential, knowing whether there are any special requirements related to potential flooding, waterproofing, and/or floodproofing in the area in which the project is located is important for all members of the project team. FEMA provides information about the flood hazards in areas throughout the country via their FEMA Flood Map Service Center, which is available on line at https://msc.fema.gov/portal.
Factory Mutual Global also offers guidance for flood prevention and mitigation in Factory Mutual Global Property Loss Prevention Data Sheet 1‐40, Flood. (Register to receive Factory Mutual Global data sheets at fmglobal.com/datasheets. Flood abatement solutions, in the form of FM Approved products, can be found in FM Approvals at approvalguide.com.)
Factory Mutual Global relatively new Interactive Flood Map is also available, which is accessible online at https://www.fmglobal.com/research‐and‐resources/global‐flood‐map. (Refer to Figures 3 and 4).
Also, as flood hazard management requirements become more stringent, some Jurisdictions are providing amendments to the Codes requiring that construction must comply with the minimum participating criteria of the National Flood Insurance Program (NFIP), the standard upon which the FEMA requirements are based. The latest edition of the International Building Code, which is becoming more and more widely adopted and/or adopted and amended by local jurisdictions, also contains requirements for construction within flood hazard areas. FEMA currently provides reference documents summarizing: the flood resistance provisions of the 2015, 2012, and 2009 International Codes (I‐Codes); the referenced standard from American Society of Civil Engineers (ASCE) 24, Flood Resistant Design and Construction; and requirements of the National Flood Insurance Program (NFIP), which can be downloaded from: https://www.fema.gov/building‐code‐resources.
Notes of Interest:
Where Flood Waters May Inundate Part or All of the Main Floor of a Building:
Among the floodproofing information provided by FEMA, which may be of interest to WSRCA member waterproofing contractors, designer, and manufacturers, is a statement related to how much of a building should be allowed to be made waterproof. In areas where flood waters can be expected to inundate part or all of the ground floor of a building, and dry floodproofing is allowed, FEMA has stated that waterproofing should not extend up more than a height of three feet, (without an engineering analysis) due to the danger of structural failure from excessive hydrostatic pressure and other flood‐related forces (e.g., from heavy floating debris, such as fallen trees etc., being pushed along by flowing flood waters).
Buildings Constructed with Crawlspaces:
Where buildings are constructed with crawlspaces under the floor, FEMA requires items or materials that could be damaged by flood waters to be located elsewhere, and it requires flood openings in the foundation walls so that high flood water is free to flow through the crawlspace without exerting further water pressure/force on foundation walls. For new buildings or substantially damaged or improved buildings with crawl spaces, flood openings are also required under the NFIP.
FEMA advises us that dry floodproofing measures may be best described as “a combination of operations plans, adjustments, alterations, and/or additions to buildings that lower the potential for flood damage by reducing the frequency of floodwaters that enter the structure.” (Engineering Principles and Practices for Retrofitting Flood‐Prone Structures, (Third Edition) FEMA P‐259 / January 2012, 5D‐1)
Note: FEMA cautions that dry floodproofing should be considered for short duration of flooding (e.g., of a few hours), and that a structural engineer should be called on to evaluate the building to determine if the wall and floor assemblies can resist the hydrostatic and other flood‐related loads the waterproofing may add to an otherwise non‐waterproofed existing building.
Examples of dry floodproofing modifications to existing buildings indicated as general guidelines in the FEMA document include:
Use of waterproofing membranes, flexible membrane flashings, sealants, and weather stripping gaskets to reduce seepage of floodwaters through walls (See Figure. 5) and wall penetrations;
Installation of watertight shields; sealants and flashings for doors and windows, and other wall openings;
Reinforcement of walls to withstand floodwater pressures and impact forces generated by flood‐water pushed floating debris;
Installation of drainage collection systems and sump pumps to control potential water entering interior levels, collect seepage, and manage hydrostatic pressures on the slab and walls;
Installation of check valves to prevent the backflow of floodwaters or sewage flows through drains; and
Anchoring of the building to resist flotation, and lateral movement.
As with all building codes, standards, and governmental requirements, the language and requirements can change from edition to edition, which may occur with FEMA floodproofing‐related documents, and the new Factory Mutual Global document. As such, it is imperative to remain up to date on the current set of Codes and verify the current codes and regulatory requirements that are in effect for your specific waterproofing project. It is also important to be aware of and understand what regulations and requirements are in place for existing buildings versus new construction, and the different requirements related to substantial improvement or damage repair to existing buildings as it relates to floodproofing and waterproofing. Waterproofing for dry flood proofing can be different from the normal waterproofing of structures (e.g., below grade) to prevent the entry of ground water.
Thank you for your participation in the western waterproofing industry. We trust the above information aids you by providing resources that can better equip you when you and/or your company may be involved in construction and waterproofing‐related work in flood prone or flood hazard areas. Thank you for your support of Western States Roofing Contractors Association, and our active efforts to strengthen and advance technology and science in our industry, as well as to promote the art of quality roofing and waterproofing.
Posted By WSRCA,
Wednesday, November 8, 2017
Updated: Wednesday, November 8, 2017
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Greetings to Members of Western States Roofing Contractors Association:
As the severity of surface weather storms appear to be occurring with greater frequency and in some areas with increased amounts of rainfall, WSRCA’s Steep-slope Committee wants to remind roofing designers, roofing contractors, and all of our members of the importance for appropriate roof system storm water run-off management. This bulletin in particular relates to steep-slope roof drainage and specifically gutters and downspouts.
Within the two primary model building codes that address storm water run-off management for the most of the Western region of the United States (The International Code Council’s [ICC] International Plumbing Code (IPC), and the International Association of Plumbing and Mechanical Officials’ [IAPMO] Uniform Plumbing Code [UPC]), the code requirements vary depending on the adoption of the model code and any amendments that local jurisdictions may have implemented.
In the International Plumbing Code (IPC), Chapter 11 Storm Drainage, published by the ICC, the installation of gutters on steep-slope roofs is not directly dictated or required. As with other model building codes, tables are included to assist with the sizing of gutters and vertical leaders (i.e., downspouts), often based on 100-year storm reoccurrence and 60-minute rainfall data. The most recent and current editions of the IPC do not provide language dictating the installation of gutters. However, the 2015 Uniform Plumbing Code and other previous editions, published by IAPMO, does state that gutters are required within Chapter 11, Storm Drainage. Therefore, it is critical to be aware of the Codes that are in effect in the jurisdiction of your roofing or reroofing project and understand the requirements for storm water run-off management. Please note that not all Jurisdictions adopt the most recent edition of the Codes, so it is important to also confirm and verify the year of the code that is in effect.
This WSRCA Technical Bulletin is intended to provide an overview of the varying code criteria and preliminary guidance for understanding model building code requirements that may be in effect for your project. In light of the magnitude of code changes over the last decade or so, WSRCA believes it is prudent that you verify which code is in place and understand the requirements that relate to your roofing and reroofing projects.
Whether your steep-slope roofing project is commercial or residential, accommodations for roof drainage and proper run-off management are among many of the most critical and primary items to consider. Model Plumbing Codes have traditionally provided sizing tables for gutters and downspouts, although gutters may not always be implicitly required. Similar language for the International Residential and Plumbing Codes as well as the Uniform Plumbing Code generally state within the first few paragraphs of the Storm Drainage chapter, as a minimum baseline, that if there is not a requirement for connection to an approved storm water system, that rainwater from roofs shall be discharged so that storm water drains away from the building.
Also, as storm water run-off management requirements are becoming increasingly stringent, some code jurisdictions are providing amendments to the Codes that state or require that roof rainwater run-off shall be collected and managed onsite in rain water cisterns, bio-swales, or rain gardens, for example, as a means to keep the below-grade infrastructure of the city’s sewer and/or storm water systems from being overloaded during heavy rain events.
Individual states within the Western region of the United States, have adopted varying editions and combinations of the Codes, with many states and local jurisdictions providing their own Amendments to base line codes. In Washington State for example, the primary model code adopted for the State includes the International Code Council series of Codes (i.e., IBC, IRC, etc.), but continues to use the Uniform Plumbing Code in lieu of the International Plumbing Code. California’s Plumbing Codes are also based on the Uniform Plumbing Code, and therefore, include the requirements, further discussed below, that states that “Roof areas of a building shall be drained by roof drains or gutters.” The following sections provide a general overview of select code language from the primary model codes that may be pertinent to your roofing project.
International Code Council (ICC) Roof Drainage-Related Information:
The International Code publishes the series of Codes, which include the International Building Code (IBC), the International Residential Code (IRC), and International Plumbing Code (IPC), etc. along with a number of other related codes sections. The most recent edition of the ICC Codes is published as the 2015 series of codes. Many jurisdictions have adopted the recent 2015 Codes; however, as mentioned above, not all city building departments or Authorities having jurisdiction adopt the most recent edition of the Codes and the effective Code for your specific project(s) need to be verified.
Within IBC’s Chapter 15: Roof Assemblies and Rooftop Structures, the Code states that roof drainage systems shall comply with sections from the International Plumbing Code (IPC). The IPC provides language in Chapter 11: Storm Drainage, Section 1101.2 Disposal, stating that rainwater from roofs shall drain to an approved place of disposal as well as language stating that “For one- and two-family dwellings, and where approved, storm water is permitted to discharge onto flat areas, such as lawns or alleys, etc. provided that the storm water flows away from the building. Section 1106.6 references Table 1106.6 for sizing requirements of roof gutters. In the 2015 International Residential Code, Section R903.4 Roof drainage, states that “unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof.”
Uniform Plumbing Code (UPC) Roof Drainage-Related Information:
The Uniform Plumbing Code is published by the International Association of Plumbing and Mechanical Officials (IAPMO). The most recent edition of the UPC was published in 2015. The following language reference is provided in Section 1101.12.1 Primary Roof Drainage stating:
“Roof areas of a building shall be drained by roof drains or gutters. The location and sizing of drains and gutters shall be coordinated with the structural design and pitch of the roof. Unless otherwise required by the Authority Having Jurisdiction, roof drains, gutters, vertical conductors or leaders, and horizontal storm drains for primary drainage shall be sized on a storm of 60 minutes duration and 100 year return period. Refer to Table S 101.1 (in Appendix D) for 100 years, 60 minute storms at various locations.”
Please Note: For those States and Jurisdictions that are still utilizing the Uniform Plumbing Code, gutters and downspouts are required as part of your primary roof drainage system for steep-slope roof systems.
As with all building codes, the language and requirements can change from edition to edition, it is important to remain up to date on the current set of Codes and verify the current codes that are in effect for your specific project. It is also important to be aware and understand what the base line size of a storm means when Codes utilize the 60-minute rainfall duration, and 100-year return period or reoccurrence interval as the basis for design of roof run-off storm water management. Recent weather data indicates that severe rain events appear to be occurring with greater regularity, sometimes far exceeding the base line threshold. With the more severe rain events, it is likely that storms may have shorter duration bursts of heavy rain with large volumes of rainfall that can over burden the storm water management systems (e.g., some gutters and drain spouts, or tight lines), which may lead to potential rain water intrusion into buildings.
Studies have also been conducted in recent years that have shown many of the industries assumptions and design criteria for dealing with rainwater run-off have been historically undersized and not adequate to properly and efficiently drain rainwater from roof systems during some storms and heavy sustained rains. New drainage design methodologies and code requirements have been introduced in select Codes, and as the information is better understood and more testing is completed, it is likely that substantial roof drainage updates will be introduced and perhaps become more widespread. As an example, the 2015 International Plumbing Code has altered the methodology for sizing of roof drains on low-slope roofs, based on recent research, and other Code groups, such as the Uniform Plumbing Code, are likely to follow in a similar manner. WSRCA’s Low-Slope Committee is working on a separate Technical Bulletin regarding the updated roof drain design requirements for low-slope roofs, and we recommend that WSRCA Members become aware of that Bulletin and the related recent updated standards.
We trust this information aids you to promote quality steep-slope roof and drainage systems. Thank you for your participation in the western roofing industry and for looking towards WSRCA to provide its members with industry-leading technical assistance for use on your steep roofing projects.
Thank you for your support of Western States Roofing Contractors Association, and our active efforts to strengthen and advance technology and science in our industry, as well as to promote the art of good roofing and waterproofing practices.
Copies of the IBC, IRC, and IPC may be purchased by contacting ICC, International Code Council at 800-786-4452 or visiting their website at http://www.iccsafe.org
Copies of the UPC may be purchased by contacting 909-472-4208 or visiting their website at http://www.iapmo.org
Posted By WSRCA,
Friday, November 3, 2017
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Dry, Safe & Secure
Home Gets New Metal Roof to Ward of Elements in Reno, Nevada
Courtesy of: Western Roofing Magazine, Marcus Dodson
Homeowners who get over 50 years of service life out of a wood shake residential
roof are getting their money’s worth. That’s what happened recently in Northern
Nevada. During the last few years of roof life there were problems: curling,
missing shingles after a wind, and then the inevitable leaks began. It was clearly
time for a new roof.
The Reno, Nevada, homeowners did some research. Since the
Reno/Tahoe area had been prone to lightning-caused fires in recent years, they
needed a Class A roof. Freeze/thaw is also a concern in this climate, and they
further wanted a roofing system that would help keep the home cool in the summer and warm in the winter. After looking into tile and fiberglass laminated shingles, they chose to go in a different direction. Decra® Villa Tile was chosen for it's classic beauty, elegance, and architectural detail of an old world Italian tile.
Steve Gubera, regional manager Pacific Northwest for Decra, said, "It is always a compliment when Decra is chosen by homeowners who have looked at many different roofing products. I feel the Decra Villa Tile was a great choice for this project not only for its appearance, but also for its performance. The location of the project is at the base of the Sierra Mountains, which gets extreme wind and weather.
Decra has nearly 60 years of experience with performance in extreme weather conditions all over the world."
Decra panels are structural grade steel, with a minimum tensile strength of 52 KSI. They are rigid enough to tolerate reasonable loads, while allowing profile designs without the risks of cracking or significant elastic recovery. The Decra Roofing Systems' design allows for roofing panels that contain numerous protective layers. Each of these layers serves the dual function of protection or adhesion for the next processing step.
The multi-layer steel panels are topped off with ceramic-coated granules and an overglaze.
D&D Roofing & Sheetmetal, Sparks, Nevada, was the roofing contractor selected for this project. Rich Borden of D&D Roofing stated that, “Our crews like working with Decra. The quality of the material is consistently good and the interlocking panels go down smoothly. Homeowners really like the Decra product line. The realistic look and depth of the panels complement custom and high-end projects.” D&D chose to get a Premium Report from EagleView® Technologies.
"The reports from EagleView make it easier for our estimators and speed up the time it takes to get our bid to the homeowner. With the report, we get aerial imagery, a 3D diagram of the roof, and accurate measurements of ridges, valleys, eaves, as well as the area," explained Borden.
While not required, the homeowners elected to have the panels installed on battens, further increasing the airflow. The system also does not require a roof tear-off, but the homeowners chose to do so. New plywood decking was installed where needed, followed by Feltex® synthetic underlayment, with CertainTeed® Winterguard(TM) HT peel and stick underlayment at the eaves and valleys. Next, the wood battens were applied, followed by the Decra metal roof panels and bird stops. The 6,500 sq.ft. roof also had two small skylights and one large skylight that had to be custom built. New gutters all around completed the project.
The Villa Tile profile that was selected for this project mimics a tile roof look, but is a fraction of the weight. The design of the Villa Tile reduces heated air entering an attic space. The barrels are 3-1/4" high, providing an offset from the roof deck, which contributes to the continuous airflow across the deck and helps to pull the heated air away from the attic. Less heated air in the attic equates to less stress on the cooling system, and lower energy consumption. In addition to being energy efficient, each panel is made from steel, which is durable and has upwards of 25% post-consumer recycled steel content. The Villa Tile installation was straightforward, with clean edges, smart elements, and natural color variations. The steel-coated panels look like clay tile from the street, but weigh much less than other roofing materials.
They are Class 4 impact resistant, freeze/thaw resistant, and steel is a non-combustible, Class A rated material.
"Decra Villa Tile has no exposed fasteners, and comes with a Lifetime Limited
warranty as well as a 120 mph wind warranty so the roof should be able to
withstand anything Mother Nature throws at it. From an environmental point
of view, steel is the most recycled product in the world. Decra is also
compatible with water recovery systems due to the fact that nothing harmful
washes off the roof as the product ages," stated Gubera. With this hidden
fastener system, the panels are low maintenance and walkable.
While originally scheduled to be finished within a couple weeks, the project
took almost two months to complete. This was due to weather delays and the need to fabricate the large custom skylight. Despite the delays, the homeowners remained content with the quality and progress of the work. They are pleased with the look and security of their new roof and now have one less thing to worry about the next time severe weather hits Northern Nevada.
Posted By WSRCA,
Friday, November 3, 2017
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A Historic Reroofing Project
Restoration of 120-Year-Old Steep Roof in Belvedere, California
Courtesy of: Western Roofing Magazine, Michael Russo
It took a wise property owner and a trusted contractor to complete a highly complex
reroof while honoring the memory of one of California’s most successful turn-of-
the-century architects. In 1898, Albert Farr designed a single building of two-story
cottages in Belvedere, California, with a dramatic 18:12 roof pitch reminiscent of the
grand English manor houses of the time. Farr designed what was dubbed The Farr
Cottages before he reached 30, but according to architectural historian Bradley
Wiedmaier, never received the full credit he deserved.
There’s little doubt Farr would have appreciated the care and concern shown to the cottages built directly off the San Francisco Bay when it came time to reroof them. He may also have looked on the scaffolding system built by Ken Cooper Roofing, San Rafael, California, as an engineering marvel in his time. President Ken Cooper spent three years cultivating this 114-squares reroof before it went out to bid. Along with their reputation, Cooper’s detailed presentation of the cost, job layout, and completion date earned him this prestigious project.
Keenly aware of the building’s condition, the client acted quickly when 20-year-old fiber cement shakes began blowing off the roof.
The shingles had absorbed moisture and had begun to fall apart under the high winds and heavy rains that commonly come off the San Francisco Bay in midwinter. Estimating the job alone had to be a nightmare, as the work encompassed 94 roof facets that forced Cooper’s six-man crew to start the job 94 times.
“We were probably getting 300 sq.ft. of shingles, hip, ridge, and flashing installed on a good day,” says operations manager Kyle Cooper. Prior to this, Kyle constructed an elaborate, multilevel scaffolding system that enveloped the entire building at the eave line and even extended into the Bay at high tide.
The five-unit building sports five docks leading to the water. With all of the tenants occupying their residential suites during reroofing, the early job planning centered on the safety of the tenants and Ken Cooper Roofing’s crew. Pedestrian canopies were set up all around the building to allow pedestrian traffic and tenants safe access to their units. Three strategically located ramps led to dump trucks at curbside, which allowed the roofing crew to efficiently dispose of roofing waste.
As luck would have it, the property owner had recently supplied its tenants with exotic Ipe wood decking.
So, Ken Cooper Roofing installed a protective board over all deck areas before setting up the scaffolding to avoid scratching the costly material underneath. The contractor went to bid without knowing the full condition of the plywood deck. But thanks to the client’s decisive action to reroof in a timely fashion, the plywood was still in good condition. However, the condition of the existing copper valleys and flashings was less desirable. Nail penetrations through the materials convinced Ken to replace all the copper flashings.
“As the project includes a GAF Golden Pledge® Limited Warranty, we wanted to construct a new flashing system from scratch,” says Ken Cooper, president, Ken Cooper Roofing.
“The copper pipe flashings and copper valleys were probably the toughest to produce due to the 18:12 pitch.”
GAF WeatherWatch® Leak Barrier was installed where roofs are most prone to leakage. These vulnerable areas include valleys, dormers, plumbing vents, wall flashings, pipe penetrations, and chimneys. The Farr Cottages also had a number of copper roof vents dispersed throughout the field of the roof. These were removed and the penetration holes covered with new plywood. Next, the contractor installed 415' of continuous 9" Cobra® Exhaust Vents at the ridges to allow greater ventilation performance.
Finally, GAF Pro-Start® Eave/Rake Starter Strip Shingles were installed at the eave and rake edges for added protection against wind-drive rain.
The company says it was rewarding to be selected to reroof such a high-profile project, and Ken Cooper Roofing has already received several calls for roof estimates in Belvedere. “It was also special that a family-owned business like ours was chosen by such a well-regarded local developer," concludes Cooper.
Posted By WSRCA,
Wednesday, October 11, 2017
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Are You Sure You Closed Your Jobsite Properly?
by: Eddie Garcia, Territory Sales Manager, Roofmaster Products Company
A customer of mine recently mentioned a story about a contractor who was performing a torch down job on a commercial roof. The foreman and his crew were closing the site, and before leaving for the day, the foreman performed a visual and touch check on the deck to make sure it was cool and not a fire risk. Later that night, however, the foreman received a frantic call from the building owner because the building was engulfed in flames.
One thought immediately popped into my head. Did the foreman walk the whole roof? Maybe the foreman only checked the immediate areas where the torches were being used. Something can accidentally begin to overheat at the end of the day, and workers packing up may not notice a small fire that can quickly turn into a big disaster after hours.
There are several regulations that OSHA has in place that help reduce the likelihood of a fire hazard, including: a fire extinguisher must be accessible for all torch-down operations; a fire extinguisher is needed 50' of anywhere where more than five gallons of flammable or combustible liquids or five pounds of flammable gas are being used on a jobsite; no one on the jobsite can be more than 100' from a fire extinguisher at all times; there must be at least one fire extinguisher for 3,000 sq. ft. of a work area; a fire watch person should be posted to immeadiately address any possible smolders or flare-ups; and the fire watch person should remain on post for 30 minutes after the torch-down job is finished for the day.
Per torch-down OSHA requirements for working with torches, at a minimum roofing professionals should have proper fire extinguishers and an infrared thermometer to scan the deck for hot spots that are undetectable to the human eye.
Contractors and foreman should take caution when it comes to torch-down roofs and be sure to thoroughly inspect all areas of the roof before shutting down for the day. Additionally, with the help of tools, such as an infrared thermometer, roofing professionals can assure that their jobsite is safe for the evening or weekend.