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Small Cabin Forum / Cabin Construction / Nail Shingles to Foam Insulation?
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Riv
Member
# Posted: 8 May 2022 08:23 - Edited by: Riv
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Hi,

We are building a 10x14 bedroom addition to our 3 season camp. The builder wants to use 1" rigid insulation on the roof and then nail shingles directly on top of that. I think this is not correct --am I correct? I also believe code states that ice and rain needs to be applied but he said it was "overkill." Red lights? State of Maine. Thanks

Fanman
Member
# Posted: 8 May 2022 08:37
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Sounds like a really bad idea. Shingles need to be nailed to a rigid surface, with only roofing felt (tar paper) in between. Insulation goes under the roof decking.

FishHog
Member
# Posted: 8 May 2022 10:14
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Sounds like it’s time to find a new builder

gcrank1
Member
# Posted: 8 May 2022 12:55
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Anybody who 'builds' can be called a builder, right....?
Competence is another thing.
Id really have to wonder about 'other things' this builder may have done that didnt come up in conversation.

Brettny
Member
# Posted: 8 May 2022 19:32
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Yup find a new builder. I'm sure the shi glen manufacturer will state on there website proper surfaces if you need more proof.

travellerw
Member
# Posted: 8 May 2022 22:15
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I was reading this post, wondering if there is something we are missing.. Surely a "builder" would not think its OK to try and nail shingles into foam. Seriously, the first strong wind and they would blow off.

Are they thinking of using long nails and hitting the sheathing underneath?

DaveBell
Moderator
# Posted: 9 May 2022 00:58
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Seems like he is taking a shortcut to save time. Tell him to nail in 2x4 blocking flat side up at two places between the rafters, 1/2 inch above the ceiling edge. Cut the rigid insulation to fit between the rafters. Lay the insulation on the 2x4 blocking. Spray foam the insulation edges. Install the plywood, underlayment, and shingles.

Brettny
Member
# Posted: 9 May 2022 05:09
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Quoting: travellerw
Are they thinking of using long nails and hitting the sheathing underneath?

Even if they did that they would still move and rip off.

paulz
Member
# Posted: 9 May 2022 06:54
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Sounds nuts to me, although I actually found one how to article.

https://homeguides.sfgate.com/put-rigid-foam-insulation-roof-before-putting-shingles- 27840.html

Everything else I saw said no way.. I would imagine a lot of people with uninsulated roofs who need new shingles wonder about the feasibility.

happilyretired
Member
# Posted: 9 May 2022 08:45
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Quoting: DaveBell
Seems like he is taking a shortcut to save time. Tell him to nail in 2x4 blocking flat side up at two places between the rafters, 1/2 inch above the ceiling edge. Cut the rigid insulation to fit between the rafters. Lay the insulation on the 2x4 blocking. Spray foam the insulation edges. Install the plywood, underlayment, and shingles.

If the builder wants to nail shingles to foamboard the best option is to dump him and find someone competent. Hiring them and hoping that they will do it right is a disaster waiting to happen.

jsahara24
Member
# Posted: 9 May 2022 08:57
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So I bought a farm last year, and when I was getting a new roof installed the roofer informed me that was exactly what he found. The shingles were nailed to 1" foam boards.

It is no wonder why that roof was leaking consistently, so I had to have plywood installed on top of the foam, then snow/ice shield, then shingles.

I would personally switch contractors...

Tim_Ohio
Member
# Posted: 9 May 2022 10:11 - Edited by: Tim_Ohio
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We just re-roofed a 1936 house. We did not know it, but the asphalt shingles that were to be replaced were installed over top of the original slated. There was only one layer. We think since 1936, it had only two roofs on it, the slate, then the asphalt. The roofers said it was the most difficult removal they had ever done. They used a white under-layment. I'd never seen this type before. It rolled out like felt, but had a backing that was removed as it was applied. I'm thinking it had an adhesive backing. I received the pics from my wife. It's hard to tell what brand they used. I'm thinking it was high quality stuff, since this job cost us 20K. It was to be warranted for our lifetime and transferable to any new owner once. In other words, we paid extra for the roof to be replace if it ever failed in our lifetime.
roof 1
roof 1
roof 2
roof 2


Brettny
Member
# Posted: 9 May 2022 10:57
Reply 


Tim that's just ice and water shield. With the way your roof is shaped it's almost mandatory that they use ice and water shield on it. Lots of dormer and valley angles in that roof.

Riv
Member
# Posted: 10 May 2022 07:01
Reply 


Thanks everyone!! You are just confirming what I thought.

FYI - this is the way the roof will look from the inside. He wants to put foam board on top and then shingles.
IMG1455.jpg
IMG1455.jpg


jsahara24
Member
# Posted: 10 May 2022 09:09
Reply 


That's a very nice look!

1" of foamboard doesn't sound like enough insulation though...May want to look into that when considering snow/ice shield, venting and condensation concerns....

Good luck

gcrank1
Member
# Posted: 10 May 2022 09:17
Reply 


Depending on your winters you might want more.
Styro atop the ceiling boards is not uncommon and there are accepted and approved methods to do so.
Your builder may need some education but likely can do it right once he knows how.

Tim_Ohio
Member
# Posted: 10 May 2022 09:25
Reply 


Based on my images, where the roofer uses the snow and ice shield, then the shingles are installed, I'd think putting the snow and ice shield on first, would be a good idea. Then, add the foam board and finally the shingles. Then, the snow and ice shield will reduce the possible leaks. It's a difficult call when you want a ceiling to look that way. It looks nice, but it's not ideal since it's not easy to insulate. The ceiling, as you know, is where you will have the most heat loss. I always liked that look, too. It's just a difficult one to deal with.

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