TL;DR: Coating an asphalt shingle roof is against code. It voids the warranty, rots the deck from inside the home, and creates new leaks. NRCA does not recommend it. If a roofer offers to coat your shingles to save money, get a second opinion before you write a check.
How a Green Valley Homeowner Almost Got Scammed: Spray-on Roof Coating for Asphalt Shingles
We had a homeowner in Green Valley call us the other month for a free roof inspection. During the inspection, we learned that another roofer had suggested that she apply roof coating to her asphalt shingles instead of replacing them. This is always I bad idea. I explained to her that doing so was against roofing codes because this would be a different roofing system on top of an older roofing system. Not only that, it would likely cause rotting of wood and most likely more leaks.
In the end, shed decided to get the job done correctly and we replaced the roof. She now has a solid roof that will last her at least 25 years or more. The cheaper bid with roof coating would have needed work in less than five years and would have cost her significantly more money. It always pays to do it right the first time.
Why Putting Roof Coating On Asphalt Shingles Always Fails
There are three things that happen the moment a coating goes over shingles. Most homeowners don’t know any of them.
1. The roof can no longer breathe: Roofs are meant to breathe—and even though on a shingle roof you have underlayment and layers of shingles, the roofing system can still allow moisture vapors from inside the home to escape. The average household releases 5 to 15 gallons of water vapor into the air every single day from breathing, cooking, showering, and doing laundry. According to the Asphalt Roofing Manufacturer’s Association or ARMA, when the moisture inside the home is sealed in by a roof coating, it can rot the deck, grow mold, and fail the entire roofing system. Ultimately, this can be an expensive fix when replacing a significant amount of rotted wood.
2. Water under a shingle has nowhere to go: Asphalt shingles are crafted in a way that allows water that gets under the shingle to escape out from the shingle underneath it. If the shingles are coated and sealed, should water get underneath, the water has nowhere to go. This can cause the water to back up and flow over the shingle, down to the underlayment, and possibly into the home. We often get calls for leaks after the bottom layer of shingles are coated where they meet a flat roof portion.
3. The warranty is voided: Every major manufacturer treats aftermarket coatings as an unapproved modification, and the National Roofing Contractor’s Association (NRCA) does not recommend coating shingles. Between 2007 and 2009, Florida Power & Light incentivized 4,700 Miami homeowners to coat their shingles for energy efficiency and this later led to a class action suit because of the damage it eventually caused.
A Tucson Home That Was 100% Damaged By Coating
Two years ago, DSR Roofing took a job where the homeowner was about to lose her insurance. The roof had two layers of shingles and the top layer was coated and three-coursed with polyester fabric. From the ground the roof looked decently strong.
Once we started the tear-off, we found that every sheet of decking was rotted from all the moisture that was in the home. Only two people lived in the home but it created enough moisture to rot out the OSB in less than four years.
The homeowner thought they were doing a good thing by adding the coating and polyester fabric but it ultimately cost them twice as much to tear off and replace the roof. Dealing with such roofs is very dangerous and roofers will likely charge a significant amount more to replace them. During this job, one of our guys fell through the decking and feet went through the homeowners ceiling in two places. Luckily, nobody got hurt.
It is Better To Replace A Shingle Roof Than To Coat It
If your roof is aged or damaged, the real options are a proper repair or a full replacement. We install Tamko Titan XT (160 MPH wind, Class 3 impact). As a Tamko Pro Gold certified contractor, DSR Roofing backs the system with a 20-year enhanced labor and materials warranty. Free inspection. Written estimate. Zero pressure.
If anyone tells you they can coat your shingles, get a second opinion before you write a check. Call DSR Roofing at 520-444-5218.
FAQs
How do I know if my shingle roof needs to be replaced instead of repaired?
The first consideration is the age of your shingles. If they are over 15 years old, they should be checked to see if a replacement is necessary. During the check a roofer should look at the granule loss, whether or not the shingles are loose or lifting, if there are damaged shingles, if the shingles are curled or missing. Another consideration is if you already have two layers of shingles, Arizona code typically requires a full tear-off before new shingles go on.
It is important to find a roofing company that will do repairs and not always recommend a roof replacement. Companies that only look at your roof with “drones” typically suggest roof replacements because drones cannot inspect a roof as good as a human could. DSR Roofing offers free inspections and we will give you an honest assessment on whether a repair makes sense. As one of our homeowners put it, “He was the only one that didn’t try to push a full tear off.” We do not push work you do not need. Call 520-444-5218 for a free inspection and written estimate.
How long do asphalt shingles last in Tucson?
Most asphalt shingle roofs last 15 to 25 years in Tucson’s extreme heat and sun. The range is extended for higher end shingles that were installed properly on a properly vented roof. The extreme UV exposure accelerates granule loss, cracking, and curling faster than cooler climates, so the lower end of that range is more common here than in other parts of the country.
Higher grade architectural shingles tend to hold up better in desert sun so it is important to choose a shingle that will last longer and has a higher warranty. We always recommend regular inspections so you can catch small issues such as nail pops, loose shingles, unsealed flashings, etc. DSR Roofing has a “Rooftop Guardian” service that services your roof every six or twelve months so homeowners don’t have to worry about these issues.
A contractor told me he can coat my shingles to save me money—is that true?
No. This is one of the most common misleading pitches in the Tucson roofing market right now. A contractor who offers to coat your asphalt shingles is either uninformed about roofing code or steering you toward a job that will fail. Coating shingles is against code, voids the warranty, and traps moisture that can rot the deck from the inside out.
It always pays to do it right the first time. If someone offers you a deal that sounds too good to be true on a shingle roof, it probably is. Call DSR at 520-444-5218 for a free inspection. Written estimate. Zero pressure.
