Shingle wrinkles

Does anyone know what causes shingles to wrinkle like the ones shown in the attached photo.
Roof is roughly 12-14 years old on a steep section of a mansard roof rougly in the middle of a 15’ long section between dormers. Single layer of roofing facing north.
Is this a problem and how should it be addressed in my report?

Looks like a raised area of sheathing…
Improper nailing and/or attachment.

Agree with Joe, sheathing underlayment expansion buckling or framing member out of plane with the others. Most likely sheathing joint improperly nailed. :slight_smile:

Could be 30# felt paper with a sloppy spot. Did you touch it to see if it was soft???
(What else could the question go for, hummm???)

Thanks guys, it did not seem like the sheathing was buckled up at this location but, was more like Sean suggested, a raised area of felt underlayment with the shingles following and I was able to push it in somewhat. It was however how vertical the line was! No attic access to see the sheathing from inside.
I included the photo and commented to “Monitor for further movement and/or leaks”.

What is it that the client is monitoring?
What baseline has been established for further deficiency to progress to?
And if additional deficiency or leakage occurs in 6, 12, 18 months…
What will you provide?


Gary did the correct thing. He observed an area that did not seem to be an issue at the time but suggested the client keeps an eye on it. Without destrcutive inspection no conclusion will be made. I bet you money its just felt paper. That stuff is a pain to run on a gambrel roof like that.

I see other problems perhaps unless it just the way the picture was taken

Looks like nails just pulled out of sheathing. If you can push in, then it is a problem for sure.

Nah… just installed by an out-of-work plumber. :neutral:

(Get it? He installed an ‘air gap’!) :roll::wink:

Well, then that’s the problem–he should have install a high loop…:roll::wink:

Soft, I’d say felt too.

Wayne, that’s just the raised dimensional tabs there. No issue.