Concerning Spray-on Asphalt Roof Coatings

There are companies that sell spray on coatings for asphalt shingle roofs claiming overriding benefits to the homeowner, such as: longer roof life, energy-use reduction, or remediation of small roof leaks. There is little to no available documentation showing the true extent of these benefits, with some having an expected life span of only a few years. While some coatings can temporarily restore flexibility and improve energy efficiency, they cannot fully repair aging shingles and may lead to trapped moisture and premature failure. They are, at best, a short-term life extension on a roof that is in decent condition. They are not a good solution for heavily worn, curling, or leaking shingles.

​Be it acrylic, silicone, polyurethane, soy, plant, emulsion, or elastomeric -based, the Asphalt Roofing Manufacturers Association (ARMA) does not recommend the application of any type of field-applied aftermarket coating over installed asphalt shingles. Their primary concerns include:

• Warranty Issues—most shingle manufacturers explicitly state that field-applied coatings will void the warranty.
• Moisture Retention—coatings can trap moisture in the shingles, leading to premature aging, mold, or rot.
• Adhesion Problems—asphalt shingles have a protective granule layer. Coatings may not adhere properly and can peel, crack, or flake over time.
• Thermal Expansion Issues – Shingles are designed to expand and contract with temperature changes. Many coatings lack flexibility, leading to cracking or separation.
• Fire and Energy Rating Alterations – Applying an unapproved coating could reduce the fire resistance and/or energy rating of the shingles.

Note: If you live in California and want to proceed, please be advised that while California's building codes do not explicitly address field-applied roof coatings on asphalt shingles, any such application must adhere to manufacturer guidelines, maintain fire-resistance classifications, and comply with Title 24 energy efficiency standards. It is advisable to consult with local building authorities or a licensed roofing professional before applying any roof coating to ensure full compliance with all applicable regulations.

The ARMA states that asphalt shingles are designed to perform as manufactured. Instead of spending hundreds or thousands of dollars on a coating with limited short-term benefits, they recommend proper maintenance and ventilation as better ways to extend a roof’s lifespan:

• If your roof is nearing the end of its life, a partial repair or full replacement may be a better long-term investment.
• Improving attic ventilation and routine maintenance (cleaning debris, sealing minor leaks) can naturally extend shingle life.
• If energy efficiency is the goal, proper attic insulation could be a smarter investment.
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Spray-on roof coatings are marketed as a cost-effective way to extend the life of asphalt shingles, but they come with some significant drawbacks. While some coatings claim to restore flexibility and improve energy efficiency, they can also trap moisture, void manufacturer warranties, and alter fire ratings. Industry experts, including the ARMA, generally advise against their use. Although coatings could provide a short-term solution, they are often not a cost-effective alternative to proper roof maintenance or replacement.