Roof shingle blisters

[dhelm]

Any one seen blistering on shingles like this? Anyone know the cause? I seem to be having trouble inserting a picture. Guess I need help with doing that.

[Joseph Hagarty, CMI]

http://www.owenscorning.com/around/r...leshooting.asp



BLISTERING



CAUSES
Moisture in the shingle

RECOMMENDATIONS
If the blisters break open revealing the asphalt, the affected shingles should be replaced.
Consult with the manufacturer of the shingles.

[Peter Doane]

Judging by the picture obviously the shingles look brittle and starting to shrink or cup under. Possibly due to extreem heat in the attic from lack of proper ventilation. IMO

[Peter C. Russell]

I agree with Peter, looks like excessive heat build up but could also be defective shingles.
All shingle MFG. have their defects from time to time but if the roof is older it's probably at the end of life expectancy

[jbreazeale]

Whenever I see that, I know there's going to be a venting problem in the attic. See too much of it down here, but I'm guessing it's probably not seen that often in Washington state.

[Adam D. Cole]

It could be a manufactures defect. I reported the same thing before and so happened to find out that Lowes was paying for half of the replacement.