They are usually formed by the pressure of moisture beneath the surface of from lack of adhesion causing dry spots.
Roof coating blisters.
Blisters may be filled with water or air.
It is now trapped underneath the coating with nowhere to go.
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.
Generally speaking unless its at a scupper or in a ponding area one broken blister is not an emergency.
These bubbles are often referred to as blisters and they are a sign that moisture has reached the inner layers of the polyurethane material.
All conventional low slope roof systems experience blisters in some form.
It is important to recognize the difference before proceeding.
Bubbles across your foam roof will look like small or large rounded domes that stick up from the surface.
Loss of gravel granules or another surfacing membrane deterioration blisters in seams which have reduced lap coverage blisters that have breaks that can.
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.
This roof has way more blisters on it than normal.
Blisters are pockets in the roofing material with a spongy feel.
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.