I would like to install my own ceiling in my new build- gable roof, see pic - two flat,slanted portions.
I don't want to use drywall, and so far I've been told that's OK. True or not?
I saw some rule that says the finish has to be at least 1/2"' thick. True or not?
I would like to use a tongue and groove type product. I have found a 5/16 pine v-joint that looks fine. If that is too thin, then I would put a 1/4 inch layer of oriented strand board underneath. Comments?
Insulation is to be blown between ceiling and roof. Is there any need for a plastic barrier anywhere?
Thank you!
Hi there,
I believe the tongue and groove pine is okay to use, but depending on the specs for your rafters or trusses, you may need some form of lateral bracing. I did not see a picture... also, you most definately need vapour barrier. It creates a barrier between hot and cold and will help to eliminate condensation and mold issues down the road.
Hope this helps,
Dave
Concerning whether or not you need 1/2 inch drywall it would be worth a phone call to your local municipality to check on their code. I do know if it's a secondary Suite It Is code to have a minimum 1/2 inch drywall with tape one coat. If you are installing spray foam insulation make sure it's 2 lb spray foam which has its own Vapor Barrier built in then you do not need to add plastic 6 mil vapour barrier
I would call the local building dept. I believe what you use on the ceiling is not there concern but what is underneath. You absolutely need vapour barrier and the required amount of insulation for your area.
Interior wall and ceiling finishes in homes are required to have a flame spread limit of 150. According to the tables in Appendix D of the building code lumber has a flame spread rating of 150 provided it is min. 16 mm thick. Your proposed solution of 1/4 OSB plus 5/16 pine would require the blessing of your local building official as others have mentioned.
You have also mentioned 'blown' insulation. If you are referring to loose fill I believe you will find that the pitch is too steep and also there is little room to work. You would probably be better off using batt insulation.
Ian Derksen
Building Safety Codes Officer
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