insulation over structural decking
mountainman72
| Posted in Construction Techniques on
I’m building a home where the great room features heavy timber trusses 4’OC with T+G structural decking above. This decking will be something like 3×6 T+G yellow pine. This decking is both visible from below, and the structural roof deck. Obviously this set up doesn’t allow for normal R30 between traditional trusses or joists. The solution seems to be rigid insulation on top of the decking, sheathing on top of that, then the roofing materials. My questions are:
Is this the best way to insulate above the decking?
How is this section of the roof vented?
Please send along any ideas; I’ve never done one of these before.
Thanks, Brett
Replies
I'd plan to use 1x6 T&G or 1xs8 T&G and then structural insulated panels.
If you use a foam and tight joints, there is no dew point allowed to encourage condensation so no ventilation is needed. Sometimes a heat recovery ventilation system is necessary though
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our commercial roofer used this on his mother's home in PA with a shingle install on top.
http://www.cornellcorporation.com/products.html
he didn't use this brand, but this is an example for you. it's a product that came from a local commercial roof material supplier.
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