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We are building a Cape Cod Cottage on Lake Huron and used 8″ Structural Insulated Panels for the roof on an open Span between the center beam and exterior load bearing walls.
My question is what is the best way to finish the inside of the cathedral ceiling, which runs the length of the wing. The pitch is 10/12, the width is 30 feet and the length of this wing is 56 feet. We want to use both tongue and groove cedar and plaster board in different areas for the ceiling. Can I glue/nail directly to the SIP panels, or do I have to glue and nail firring strips first? Should the tongue and groove be glued, or just nailed? I’m worried about gluing since I don’t want cracks due to shrink – we see lots of weather change in Michigan, especially on the lake.
Thanks.
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Robert,
I don't have an SIP roof but I did use tongue and groove in my "witch's hat" (turrettower whatever you call it in your neck of the woods) ceiling. I nailed mine but DID NOT glue it. I figured the nails will hold it where I want it but the t & g is allowed to expand and contract with temp. and humidity changes.
Much the same way you never glue flooring.
My guess in your situation is that you would want to use some means of nailers (firring strips) as I would think you would want some air space between the panels and the ceiling material. Otherwise wouldn't the ceiling material even take more of the temphumidity changes from being in direct contact with the roof panels?...
Mike
*Mike, thanks for the fast response. The reason for my question is pretty much the question you finished your answer with. I don't think 7" of Expanded Polystyrene Foam in the center of an inch of OSB covered with roof felt and shingles is going to pass a lot of water or moisture, so I don't think nailing directly to the panels would be a problem in that respect. But, I don't know, and given the cost and time this project is going to take, I want to do it right. Therefore, my posting the question to this panel of true experts!The conservative answer seems to be firring (or furring?) strips, but are they really necessary, and do they bring any real improvement to quality? The SIP panels are very smooth and uniform - a big advantage to using them. I think both the drywall and T&G will look great to start - but how about a year or 10 later?Thanks.RobertJ
*Robert, Yes, I agree that 7" is quite a way for moisture to pass and that nice smooth surface is hard to pass up as usage as a nailing base. I guess the paranoid side of me would just want a little air space between the finished t & g and the panel. Even though its only 3/4" (furring thickness) I would still be happier that way. My thinking is just that direct contact "might" (keyword here is "might") result in a great possibility of conduction of temp and humditiy occurring but if an air space is there, full conduction possibility is reduced.Mike
*You might be interested in taking this question here:http://www.sipweb.com/Forum/forum.asp?FORUM_ID=1&CAT_ID=1&Forum_Title=SIP+Talkit is where the "professional" SIP people hang out.
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We are building a Cape Cod Cottage on Lake Huron and used 8" Structural Insulated Panels for the roof on an open Span between the center beam and exterior load bearing walls.
My question is what is the best way to finish the inside of the cathedral ceiling, which runs the length of the wing. The pitch is 10/12, the width is 30 feet and the length of this wing is 56 feet. We want to use both tongue and groove cedar and plaster board in different areas for the ceiling. Can I glue/nail directly to the SIP panels, or do I have to glue and nail firring strips first? Should the tongue and groove be glued, or just nailed? I'm worried about gluing since I don't want cracks due to shrink - we see lots of weather change in Michigan, especially on the lake.
Thanks.