Get the Scoop on Asphalt Shingle Coating
You may have seen advertisements for roof sealants designed to be applied directly to asphalt roofs. Such sealants are supposed to stop leaks, extend the life of your roof, and prevent the growth of mold and mildew. Other sealant products for asphalt roofs consist of white reflecting coatings
Posted — UpdatedWhat's the skinny on these products? What exactly are they, how do they work, and more to the point, do they work at all? Are they a good choice for your roof?
Let's talk about sealants first. These products are made from an acrylic that can be sprayed or rolled onto a clean roof. While it goes on white, it dries to a clear finish so the existing shingle can be seen underneath. The explicit purpose of a sealant is to extend the life of the roof by protecting the shingles, and while manufacturers don't offer a guarantee on wind damage, many claim that sealants can help prevent shingles from being torn off by storms.
Using a sealant may extend the life of a roof by a few years, but roofers note the claims of 10 or more years from manufacturers aren't supported by what they see on the job. At best, sealants can be a stopgap measure to keep a roof going for a few more years. And sometimes they can even damage a roof. One big concern is that a coat of sealant could disrupt the natural permeability of the roof, which means it won't ever get a chance to fully dry out, and that could lead to condensation inside the roof as well as the attic. That's bad news for joists and other structural components of the roof!
While sealants aren't universally a bad idea, you should definitely consider them carefully before applying them. Talk to a roofer about your options, and get an estimate on several different approaches to the issue you're trying to resolve. If your roof is heavily worn and you're trying to get a few more years out of it, for example, your roofer may have some bad news for you: it could be time for replacement. If, on the other hand, you have a fairly new roof in good condition, a sealant might be a good choice.
Sealant technology and roofing technology are both in a constant state of evolution. As the roofing industry adjusts to the entry of sealants into the market, it's also working with manufacturers to develop products that work well with a variety of roofing types. Make sure your roofer knows about the latest trends in the industry to ensure that you get an accurate and honest appraisal of the situation from someone who's familiar with all the available options, their risks, and their benefits.
And don't be afraid to get quotes from a couple of different roofers to gain a complete understanding of the picture. You may find that there are some significant differentials in estimated price as well as options for the job; find out why some roofers advise against coating, for example, and if a roofer offers an unusually high or low bid, press for details. Anything involving your roof is a big decision, because it's a key component of your house: take the time to make sure you make a good choice.