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General => General Forum => Topic started by: spc on June 08, 2011, 08:01:07 AM

Title: Ventilating an open cathedral ceiling
Post by: spc on June 08, 2011, 08:01:07 AM
Hi all,

Found this forum recently and thought maybe someone could help me out with my pending ceiling installation. I recently bought a small cottage that needs some work in order to get it winterized. The main room of my cottage is 20 x 11 with a screened in porch on one side. The ceiling is exposed right now, and I am looking to insulate and vent it. I want to use roof louvers combined with soffit vents. As that the screened in porch on one side has an extended roof, would it work to install a soffit with vents on one side of the cottage and the roof vents on the opposite side of the roof?

Also, if I install a soffit vent, I assume that the path from the vent to the fiberglass side of the insulation must be unobstructed. Would something like durovents provide an adequate air path?

Thank you,

Sean
Title: Re: Ventilating an open cathedral ceiling
Post by: John Raabe on June 08, 2011, 11:40:48 AM
Sean:

Any type of vent baffle could work.

http://www.adoproducts.com/duro.html - Durovent
http://www.adoproducts.com/provent.html - Provent

You generally want about a 1" airspace between the roof sheathing and the insulation and that should be continuous from either vent blocking (at the wall line) or eave soffits to the vent at the top which can be a continuous ridge vent or vent hoods that ventilate each rafter bay.

I like a ridge vent as it will replace a forest of hoods.

(https://i1009.photobucket.com/albums/af219/countryplans/vent.jpg)

If you do spray foam insulation some jurisdictions will not require venting of the rafters in a cathedral ceiling. This will give you much better insulation in the usually small depth of the rafter.