[This was also posted in alt.home.repair. Found this group afterward.]
I am re-roofing my house. On the two rear corners are small (10x12 or
so) flat roofs covering additions. These have given problems from day
1 in spite of having been re-done twice with tar and gravel.
This time, I wanted to cure the problem and elected to go with a
rubber membrane system. Upon applying the membrane, there were small
blisters (1"x2" or so) all over the roofs. The contractor said that
this was due to heat buildup because of the glue and that they would
go down overnight. They didn't. When they applied the membrane, I
don't think they used a roller to force air out. This is early AM, and
I don't know yet what they will be doing today.
What should I think of this, and how should I handle it?
Blisters are not good. Not sure what type of membrane you have, how
the roof deck was prepared, etc., but it sounds like the contractor
rushed the installation. If the adhesive isn't allowed to flash before
the membrane is installed solvent blisters can appear. Usually this is
more of a problem in colder weather. Or you may have air bubbles
which, as you mentioned, is from not rolling out the membrane properly.
The blisters have to be patched. Many blisters all over the roof is a
reason to have them redo the membrane. This is the general repair
procedure (taken from a manufacturer's web site):
7. REPAIRING BLISTERING AREAS.
a. Fully Adhered Systems. All blisters or
delaminated roofing must be repaired by cutting
blistered area in an "X" pattern where moisture
and/or contaminates can be removed and
properly cleaned. With material pulled back,
apply ASTEC #2000 Flash Grade Waterproof
Membrane 30 to 40 wet mils in the
delaminating area. Then fasten "X" down.
Once this area has properly dried
(approximately 24 hours), using ASTEC #2000
Flash Grade Waterproof Membrane fully cloth
and embedded over these repair areas using
the 3-step flashing system.
b. Non Adhered Systems (loose laid). Follow
EPDM manufactures recommended
specification procedure for EPDM repair using
ASTEC #2000 Flash Grade Waterproof
Membrane apply 6" wide polyester cloth with
12" wide application of #2000 Flash Grade
Waterproof Membrane over the repaired lap
seams using the 3-step flashing system.
1. ASTEC #2000 Flash Grade Waterproof
Membrane @ 82 sf/gal applied 12" wide.
2. 6" Polyester Cloth embedded into first coat.
Let dry 2-4 hours.
3. 12" wide apply second coat ASTEC #2000
Flash Grade Waterproof Membrane over
repaired area @ 82 sf/gal assuring no pin-
holing in repaired area.
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