How do you repair a foam roof blister?

Foam Roof Blister Repair

What causes roof blisters? Roof blisters form as a result of moisture or because of poor ventilation. If the blisters are a result of moisture, you’ll start seeing the blisters forming within a year of getting new asphalt shingles. Moisture can become trapped in shingles due to errors during the manufacturing process.

Blisters are now usually formed when volatiles flash out of the asphalt in newly installed shingles. This is caused by excessive heat from poorly ventilated and over-heated roof systems. … Even though blistering is often perceived as a manufacturing defect, it’s usually caused by poor ventilation of the roof system.

1. Cut the blister out using a razor knife (bread knifes work the best). This is a golfball sized blister.
2. Fill the hole with a polyurethane caulking.
3. Tool the caulking with a piece of cardboard or putty knife. Make sure you tool the caulking past all of the edges. …
4. Coat the repaired area with an elastomeric roof coating.

With that being said, the cost of a square of foam will vary from roofer to roofer. A spray polyurethane foam roof can cost between $250 to $300 per square for the first 1” of foam. Meaning if your home’s roof is 2,400 sq ft, a new foam roof could cost $6,000 to $7,200.

If properly maintained, foam roofs are long lasting. There is some maintenance, though. Every 10 or 15 years, depending on the type and amount of coating installed, the roof will need to be cleaned, primed and recoated. If this is done, then a good-quality SPF roof could last 50 years or longer.

According to some roofing experts, a 2,200 to 3,400 square foot roof with asphalt shingles could run between $2,000 and $6,000 if you do it yourself, whereas a professional roofing company will charge around $10,000 or $12,000 for architectural asphalt shingles.

While roofers typically offer estimates for free, an inspection can cost around $200 or more depending on your area. … If you already know you need a new roof, you can skip an inspection. Just ask for an estimate to find out how much repairs or a new roof will cost.