Roof Coating Blisters

It is important to recognize the difference before proceeding.

Roof coating blisters.

Bubbles across your foam roof will look like small or large rounded domes that stick up from the surface. Membrane systems are most susceptible to blistering because blisters are formed by voids between the plies or at the point between the substrate and the membrane. Loss of gravel granules or another surfacing membrane deterioration blisters in seams which have reduced lap coverage blisters that have breaks that can. Foam roofs are made from spray foam polyurethane by mixing two different materials together.

When you coat a roof you seal moisture inside the substrate. When the roof heats up due to the sun or internal building heat this moisture evaporates and becomes water vapor that expands by up to 1300x its volume. These bubbles are often referred to as blisters and they are a sign that moisture has reached the inner layers of the polyurethane material. Once broken water is more likely to get under the coating or leak into the roof.

It is now trapped underneath the coating with nowhere to go. Blisters may occur below or between ply sheets in a built up roof system at the roof coating interface with the roof surface or between coating layers when multiple coats have been applied to the roof. All conventional low slope roof systems experience blisters in some form. They are usually formed by the pressure of moisture beneath the surface of from lack of adhesion causing dry spots.

Blisters are pockets in the roofing material with a spongy feel. Most blisters are caused by the same thing moisture.