Now, isn't this nice?

[chrisprickett]

This is a four year old roof. I wrote it up as needing replacement becuae of excessive blistering. The owner called the builder, and their roofer said it was only "minor", and they would not replace it.

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[Jim Katen]

Originally posted by chrisprickett

This is a four year old roof. I wrote it up as needing replacement becuae of excessive blistering. The owner called the builder, and their roofer said it was only "minor", and they would not replace it.

Download Attachment: blisters.jpg

154.63 KB

I wouldn't describe that as blistering. It looks more like a typical asphalt roll roofing that's expanded since it was installed and is now wrinkled. (Please tell me that's not a torch down membrane.)

If it is regular old cheapo roll roofing, that's just how it behaves, at least up here. Of course, I wouldn't expect to see it over a house. In my area, it has a service life of about five years. In your area, I'd expect it to be even less. We only use it on sheds. And at that, on sheds we don't particularly care about keeping dry.

If that's a torch down membrane, it's just f---ed.

- Jim Katen, Oregon

[RobC]

From my perspective, and I may be wrong on this one, I see a quality concrete tile roof with a flat roof (less than 2:12) attached to it.

My concerns would be the flashing at the junction and the direction the membrane has been installed.

The illustration below depicts the correct orientation.

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I'll guess to say that it's not selvage (rolled roofing) by the evidence of the black line at the lap. I suspect it's been torched and the bleed is indicative of correct torching technique.

I'm thinking this roof is not attached to the decking and is either slipping OR

It was installed over a recently rained on decking and has now trapped moisture that is causing this blistering.

I agree with your call, there is more going on here than meets the eye.

What's under this roof and is it vented?

[Scottpat]

It's hard to tell but it looks like the material is 3-4 feet in width almost like roll roofing, but it also looks like an EPDM or PVC material.

[hausdok]

Yeah,

It does look like a granule-coated modbit surface. In which case, I concur wholeheartedly with Jim's assessment.

OT - OF!!!

M.

[chrisprickett]

It's a rolled comp, not sure if they torched it or not, they do both here. It's over a patio, just like a million other houses in AZ. No ventilation, which I also wrote up, and speculated that that MIGHT be a contributing cause. The condition is known a blistering in AZ, as per the Registrar of Contractors's terminology. Bottom line: it's wrong, and the roofer or builder is not stepping up to make it right.