What is causing this?


My dad recently had his 150 year old barn roofed this summer. Three layers of asphalt shingles were removed and 1 layer of cedar shake under the asphalt. They then sheethed the roof with osb.

I am really baffeled what could be causing this irregular “humping” in the shingles. To me, it dosen’t seem as if they forgot to nail an edge of osb. it is too irregular. I can not get a first hand look at this as my dad lives in CT. I told him to go and look to see if it was the osb warping away from the rafters.

One note, he now says the buckels have gone away now that it is winter.

Any thoughts, could it be wrinkels in the black paper???

Thanks Ben


I want to post a pic but am having trouble doing it.

Any hints?



You have to upload your photo to a hosting service like photobucket or something first. Then copy the url into the insert image tool.


You can also load your picture into paint, re-size it down to about 30-40% and load it with the IMG button above.


What is paint?


I think your right with the wrinkles in the tar paper. I’ve seen it many times. Usually when a lower grade felt is used. When the light is right you can see the outline of each sheet. The vertical seams are usually the most visible. My guess is its caused by the osb gassing off as it seams to lessen with time. There is a house by me that I noticed this on for the first few years.

Paint is a microsoft editing software thats usually loaded on PC’s


i know what is it.

i have seen it 3 times this year 2 times on barns and 1 time on a house that did not have insulation. the jobs looked great for the first month or so then started this. one would think it was the seems of the osb or plywood where buckling. it was not. it was the hot or cold air blowing through the joints in the decking and wrinkling the paper. in turn pushing up the shingles.


what town in CT is he in?


Why don’t you call up the roofers who installed the roof and see if they now what the problem could be?

The installers should really come back and check it out as there could be many reasons for the “humping”.

Perhaps the osb wan’t really nailed enough.

You paid for the roof and I am sure your roofers will be glad to address your issue.


if the humps or buckles are in a strait ,vertical or horizontal, line then it may be wood related.
if the buckles are runnin in any direction then they are most likely caused buy the felt paper.
someone nailed the shingles over wrinkly felt.

either way youll have to give it some time
to see if it will lay down.




If he put 3 tabs back on, every bump and wrinkle will
telegraph through that type of shingle worse than
a laminated shingle would.


Well i still have not had time to try to post a pic, but i think that the wind is an optionor the black paper. the humps are just so irregular that it cant be wood related.

Wadman, that is interesting, he too is in winsted. He lives on an old farm onn Colebrook rd. Maybe you were the roofer, i dont know. If you wernt I wil find out who it was. I think he tried to contact the roofer in August, when the buckels appeared but not since then.


I think this may be my problem. I can only see the “humps” along the plywood joints and i can push the humps down. What can be done to solve this problem? This is on a covered patio roof. It is not insulated, I have a soffit lid and it is really prominent on side with the hump getting smaller as you move to the other side of the roof.