In this tutorial I’m going to show you how to repair blisters on your foam roof. Foam roof blisters are not uncommon and are relatively easy to fix. There are many things that can cause blisters please refer to our F.A.Q for common causes.
Normally blisters are not that big of an issue to be concerned with. Unless you have alot of them , They are unusually big or they are broken. If the blisters are broken then prompt attention is needed to fix them because they can be a source for leaks. It should also be noted that blisters bigger than a baseball should be fixed by a roofing contractor who does foam roofing.
Blisters are fixed as a part of a routine roof re-coat.
In this first picture it identifys a golf ball size blister.
Step 1.
Cut the blister out using a razor knife (bread knifes work the best).

This is a golfball sized blister
Step 2.
Fill the hole with a polyurethane caulking. DO NOT use any other kind of caulking your repair will fail.

Use polyurethane caulking to fill the repair area.
Step 3.
Tool the caulking with a piece of cardboard or putty knife. Make sure you tool the caulking past all of the edges.

Tool the caulking
Step 4.
Coat the repaired area with an elastomeric roof coating. This is a permanent repair.
This is the same process a roofing contractor will use to fix blisters that are baseball sized or smaller and less than a 1/2 inch deep.
Below is a picture of a blister that you should not attempt to fix. If you have one that is broke and might be leaking you can caulk it then have it repaired later.

Volleyball size foam roof blister
One thing that often damages a urethane foam roof is bird and bee damage. This type of damage is usually found near the edges of roofs or on top of parapit walls mostly on roofs with overgrown trees hanging over the top. What happens is birds peck holes in the foam and then the bees come and tunnel through the holes. This kind of damage is very easy to fix if caught early, but if left ignored it can cause extensive costly damage. I have seen complete walls and edges in need of complete tear off and re-foamed because this type of damage was ignored. The reason birds and bees do this is because one of the main ingredients in foam is sugar. Some ways you can help prevent this is by
1. Keeping trees cut back from the roof.
2. Place rubber snakes or plastic owls in the areas that are being effected.
In this tutorial I’m going to show you step by step how to fix this type of damage.
Things you will need:
1. Polyurethane caulking, DO NOT use any other kind of caulking they will not work (especially silicone) it will popout of the hole like a plug due to expanding and contracting.
2. A piece of cardboard or something similar to tool the caulking with.
3. elastomeric roof coating, disposable paintbrush and gloves
4. caulking gun.

This is what tey call bird and bee damage
Step 1.
Clean off the oxidized foam with a fingernail or brush.
Step 2.
Fill up hole with caulking.

Fill With polyurethane caulking
Step 3.
Tool the caulking with cardboard or putty knife, apply a little pressure to make sure the caulking is down in the hole.

Apply a little pressure to ensure the hole is filled
Step 4.
Apply a generous coat of elastomeric roof coating over the urethane caulking. This is very important with out this coating the suns uv rays will destroy the caulking and your repair will fail.

The finished repair
Your repair is finished. if you followed this tutorial step by step This repair is a permanent repair and no further action is required. This do-it-yourself repair can save you hundreds of dollars.