“Who and How” of your building envelope installation is VERY IMPORTANT to your home’s health and longevity!
You may not know this, but when you decide to renovate your home with a major component in the building envelope like roofing, siding or windows, a lot, if not most of the risk of failure of that component and resulting water intrusion lies in the correct installation of the component. We all know that contractors and building supply companies would rather have us buy the premium product, rather than the mid- or lower-tier product. Some manufacturers have longer “warranties” for their premium products, and these are tied to different specs of the product. For instance, shingles come in single-layer 3-tab shingles (“builder grade”) that last about 15 years, architectural shingles are 2 layers of asphalt that are bonded together, as well as heavier that last about 25 years or longer, and luxury or premium shingles, which are even heavier, more alike to slate and wood shake shingles in appearance, and last about 30 years or longer. (What are the three types of asphalt shingles?) These types have increasing price points from 3-tab to premium, with corresponding “lifespans” and increasing wind resistance, but here’s the thing: a roof will fail in the same short time no matter which shingle is installed, if it’s installed incorrectly.
For this reason, if you are planning to make an expensive investment in your building envelope where water intrusion, mold, and your family’s health is on the line, it’s best to make sure you spend as much time researching the “Who” and “How” of the installation, as the products you’ve selected to install! First, the “Who”. There are many things that can go wrong in installation, but let’s go through the preliminaries first: a roofing contractor needs to carry both liability insurance and workers' compensation insurance, and a regional license if necessary. These are just basic things to keep you covered in case someone gets hurt, or the building inspector comes by. Next, and here is a gauge of the contractor’s confidence in his workmanship: is there a workmanship warranty? Can you call back the contractor if you have problems within a few years’ time? A contractor’s workmanship warranty and the product manufacturer’s warranty, are key documents that cover your roofing system. (Roofing 101: Evaluating Contractors)
The other key requirements of your research is business longevity and references. If a roofer has been in business less than three years, you run a risk that they are unstable, because the failure rate among small businesses within three years is high. A roofer should also be able to provide 5-10 references of recent customers with their names, addresses (so you can drive by and see the work) and phone numbers, so that you can survey their experience. You will not be able to watch every aspect of their work on your home and their installation techniques, so past customers and their perception of quality work will have important input for your decision.
Sometimes you can find a product manufacturer who also does the installation; this is more common in window companies, like Window World and Anderson. Just like having the car dealership (where you purchased the car) do the maintenance and repairs on the car, sometimes this is better, because these two warranties (product and installation) are merged into one, and window manufacturers are, generally, larger and more reputable than installation companies. However, this can also backfire, as large companies also have large legal teams who may do their best to put the blame on another faulty aspect of construction.
Finally, the complexity of your installation matters. Peter Yost, a building science expert, says, “Many window manufacturers are connecting their warranty to, you must install it the way they describe and with the materials they describe. And also, either extending the warranty or making the warranty dependent on, you’ve gotta do a (blank) certified window installer.” Sadly, money (expensive homes and expensive contractors) does not guarantee that your product will not leak. Peter also related some consulting experience: “I got involved in three projects…where the windows leaked. These were top-notch building professionals, and they were installing very expensive windows in very exposed locations, and all three windows leaked, and they leaked because, despite the fact that there was adult supervision from a water management perspective, and the carpenters were doing their best… they got installed incorrectly. And in each of the three cases it was because the people doing the work were being asked to do different types of details for different situations. You know, a flanged window vs. an unflanged window, a triple pane vs. a double pane, inset vs. flush to the outside, and there were enough of these variables that things didn’t get done right…Particularly with deeper assemblies or more exterior insulation, the window installation details are very complex and they change from jobsite to jobsite. What if we could create a more uniform process to install windows?” (UnBuild It: Episode 140: Window Installation: Can We Do Better?)
Peter then went to a car company to see how they seal car doors and windows. The big difference between car doors and home windows are…gaskets! Car door gaskets are continuous, double gaskets (double gaskets not necessary for home windows), that have fin gaskets at the top that act as gutters to guide water to other places which shield the other gaskets with air pockets (similar to 2-stage joints in commercial building facades). Until we get those gasketed windows and self-nailing shingles, however, here are the takeaways:
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Who: Select your contractor just as carefully (or more) than every component on your building envelope, because installation is just as important as the hardware you’re installing.
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How: Ask questions to understand (and make sure your contractor understands) every detail of the water, air, vapor and thermal control layers of the installation, which are integral to your home’s longevity and comfort. If there are ways to make things more simple for the contractor without violating component warranties (such as selecting a large number of similar windows), it may be worth compromising your design in order to achieve near flawless installation. Workers are human, after all, and they have the same limitations we all face on the job, so simplification will work to your advantage.
Photo by Zachary Keimig on Unsplash
