How To Fix A Spray Foam Roof

15 February 2018
 Categories: , Blog


If you have a spray foam roof coating, you may need to repair it occasionally. Spray polyurethane foam is a plastic roof coating is made from isocyaniate and polyol, which is applied to commercial and residential make a seal.

Spray foam coatings commonly last a long time, but they cannot resist UV light very well, which causes damage. You should be able to fix the foam yourself by following these tips.

Prepare to Fix the Roof

To fix the foam roof, you need:

  • work gloves
  • ladder
  • push broom
  • tape measure
  • bucket 
  • hose or pressure washer (optional)
  • mild dish detergent
  • roofing knife
  • caulk and caulk gun
  • foam kit 
  • polyurethane sealant

Place a ladder on sturdy ground, and get someone to hold it for you. Avoid placing ladders against gutters, because it could damage them. An A-frame ladder is ideal for avoiding damage to gutters. For extra safety, tie a safety harness to the opposite end of the roof. 

Wear old clothes, because this type of coating will not wash off in a washing machine. Try to work during a 4-day dry spell, so materials can dry faster.

Climb the roof, and sweep all debris. Squeeze some dish soap on the roof, and rinse it with a hose or bucket of water, then let it dry. If the roof is especially dirty, use a pressure washer.

Assess the Damage

Note the number of dents or cracks in 100-square foot areas. It should be easy to locate damage, since foam roofs are comprised of closed cells, and open cells resemble a sponge. Many small punctures and cracks can be filled with caulk. 

Measure the hole or crack at the widest part, and then measure the depth. If the roof has more than twenty cracks or holes more than three-fourths inches wide and one-fourth inch deep, half the roof will need to be recoated. Extensive damage will require the whole roof to be recoated or professional repair. 

Repair the Damage

Use the roofing knife to remove wet sections of foam, making a tapered cut around the edges at 45-degrees and let the roof dry. Fill small holes or cracks up to three-fourths inches with caulk, and let it cure.

Repair large holes or cracks by spraying the foam until it is level with the rest of the roof. It may be best to apply the foam in the hole in one-fourth inch layers, letting each layer dry separately. 

Let the foam dry fifteen minutes, then trim extra foam with the knife. Allow the material continue to dry overnight, then apply a polyurethane sealer.

For more help, contact a commercial roofing repair company.