# Roof Buckling



## daldelta (Nov 15, 2012)

Brand new home, not even completed. What wood cause the roof to do this? Bad Shingles,installed incorrectly? Thanks for your help Dave


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## joecaption (Nov 30, 2011)

Looks to me like it's the sheathing that buckling not the shingles.
Should be able to see this from the attic.
Not nailed in the middle of a rafter,
Not leaving a gap for expantion.
Under sized sheathing.
Sheathing got wet before the paper went down.
Any of these can cause it.

Anyway it's a do over do not let them get away with it. It's not go to just go and get better.


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## ParagonEx (Sep 14, 2011)

The framing. I see this a lot actually and usually you only notice it at certain times of the day. I have always found it to be more cosmetic than structural.

It has nothing to do with the shingles or the roofing materials.


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## daldelta (Nov 15, 2012)

Joecaption and ParagonEx: 
Thanks for your replies: Both of you have hit on some issues that did occur. We did have a lot of rain before the shingles were installed and the sheathing (solar board aluminum backed) did get very wet. I also noticed after the paper was installed on the sheathing it would wrinkle up when wet and then lay flat after it dried. I did see spots that were wrinkled up as they put the shingles down, although I doubt that the paper could cause the shingles to lift. ParagonEx—the shingles do only raise/buckle at certain times of the day or at least are only noticeable at certain times. What causes that? You mentioned the framing was incorrect, what would have been done incorrectly that would cause this to occur? Also wanted to mention this seems to occur starting around the dormers’ and progress up towards the peak as shown in the pictures, but not always the case. How do I logically approch and dissect this problem? Do you guys feel the shingles and possibly the sheathing should be replaced? I do not want the builder or his roofing contractor to replace only the areas that are raising now and a year or so from now the same thing happens again in other areas and I get stuck with the repair bill. My builder is a good builder and has built similar style homes without the roofing issues and would not purposly cut corners. Any more suggestions, input, or observations will be greatly appreciated. Thanks again, Dave


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## joecaption (Nov 30, 2011)

If the papers not flat or there's traped moisture trying to excape causing the paper to wrinkle is can lift the shingles.
I still think it's the sheathing causing it. The reason being is the spacing and the way it looks like the flaws are horizontal and about 4' long. With where the butt joints would be where it's the weakest.


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## pwgsx (Jul 30, 2011)

Looks like they better rip that all off and start over, I would not pay until they do.


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## jagans (Oct 21, 2012)

*You Have a Significant problem*

I was just responding to this issue and the page timed out on me. It appears that You have several significant problems. Do not pay for this roof until you have them resolved. email me so we can discuss off post. I am a registered roof consultant.

Thanks, JimA


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## BigJim (Sep 2, 2008)

jagans said:


> I was just responding to this issue and the page timed out on me. It appears that You have several significant problems. Do not pay for this roof until you have them resolved. email me so we can discuss off post. I am a registered roof consultant.
> 
> Thanks, JimA


_The forum rules frown on directing another member to email another member for instructions as this is DIY forum and your answers may be of help to other members also, thanks.
_ 
BigJim


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## jagans (Oct 21, 2012)

*To Big Jim*

These people have a problem that is going to end up in court, I guarantee that. They need professional help, Jim, not speculation, which is what most responders are doing here. The one that said rip it off and start over is correct, but they cant start over with the current design if what is there is what I think is there.

JimA


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## Evstarr (Nov 15, 2011)

Then tell us what you think is there so we all may learn


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## joecaption (Nov 30, 2011)

It's ok to share this is not the masons.


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## jagans (Oct 21, 2012)

*Assume*

Apparently I have not kept up with the latest trends in steep roofing. I assumed, and you know where that gets you, or me in this case, that the sheathing that they were using was a rigid foam product with aluminum backing. It is not. (Unless the owner says different) It is plywood or OSB with an aluminum foil backing. The installation method for this product is the same as conventional CD-Exposure 1 Plywood, which is often misnamed CDX. 

Roof sheathing is supposed to be nailed with minimum 8d nails 6 inches on its short ends, and 12 inches on center intermediate. The usual causes of buckling are as follows:

Sheathing installed butted. There needs to be an 1/8 inch gap on all sides. This is one of those funny ones where the contractor can end up doing right by doing wrong, twice. If they leave the sheathing out in the weather, it absorbs moisture and swells. They then install it on the roof wet, or damp, which is usually the case. After they install the underlayment and the roof is dried in, the sheathing shrinks, and no buckling occurs. If they keep the plywood bone dry, and do not intall it with a minimum 1/8 inch gap all around it can buckle under heat load. This is what happens with regular sheathing. I would imagine that this would be significantly amplified with a radiant barrier behind the sheathing to "cook" the plywood. it would also have the tendency to "cook" the roof shingles.

As far as what is going on on this particular house, it is impossible to be certain without an inspection, but I have seen this many times when a heavy weight organic based #30 felt is used to dry the house in, it then gets wet, and the shingles are installed over wet felt. 

The felt may not feel wet to the touch, and it might lie fairly flat when open to the air, but once the shingles are installed, it buckles, as the sun heats it up. The result is that the felt pushes the shingles up between fasteners. A foil backed sheathing would exacerbate the problem of anything wet in the roofing matrix by not letting moisture escape down through the deck. The buckled felt may go down in time, and it may not. What can be seen in the pictures is not representative of butted and buckled sheathing. That usually shows up as 4 foot long vertical ridges every eight feet. staggered throughout the roof deck.

As far as having a vapor retarder somewhere in the middle of the roofing package, I don't like it, and would not do it. There should be one vapor retarder on the warm side in most cases.

As far as laminating two materials together that have a much different rate of change under thermal load, this has never worked well in the past and it flies in the face of physics. Will it work this time? its anybody's guess.


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## daldelta (Nov 15, 2012)

*Still learning*

Thank you all for your replies and help. Jagan thanks for expanding and sharing with the group your experiences. It sounds like the consensus is the sheathing or installation of, is probably the root of the problem. Here is some more information based on your comments. I found a piece of sheathing in the scrap pile. The sheathing is made by Norton and the printing on the board reads “install foil side down”, “space all edges 1/8”, “protect from moisture prior to and during installation”. I know we had lots of rain during the roofing timing, and the paper was wet in areas when the sheathing was applied, although I believe most of the wood was covered and stacked vertically prior to installation. 
This group has done a great job informing me of what the issue probably is; now with further investigation from me I have the challenge trying to prove what happened and what all should be replaced. Unfortunately, none of the parties (shingle supplier,framer,or builder) will probably want to take responsibility and a lot of finger pointing will happen between them. If the builder implements patch fixes, I may end up agreeing with a signed stipulation if it happens anywhere else he is fully responsible and will replace the roof. Not sure what else I can do. It’s looking as I will be the end loser without hard evidence of exactly what happened. 
I still welcome any more replies and suggestions that anyone cares to contribute. FYI- The roof was installed appx. 2 months ago. I first noticed the lifting issue shown in the pictures about a week ago; the roof looked perfect to me up until then. The home has 6 dormers on it and the entire dormer roofs seem to be fine, the lifting looks to only occur on the main roof which I believe is a 12/12 pitch or close to it. I live in Tennessee and the current weather is 40’s at night and in 60s during the day. The lifting is only noticeable at certain times during the day; I would guess thermal expansion (CTE) of the different materials would apply as mentioned by Jagan. There is a ridge cap on the peaks and dormers to allow breathing. Not sure if installation of this could affect the issue, it’s a molded plastic and came in a roll. The solar board does get very hot.
Thank you all Dave


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