Sometimes, these air flow channels are mounted over a layer or two of rigid foam. It’s also attainable to buy nailbase (a sort of SIP with OSB on one particular facet instead of two) that includes integrated ventilation channels among the OSB as well as rigid foam; a person manufacturer of these panels is Great-Vent from Hunter Panels.
A vented cathedral ceiling only makes sense if the geometry of your respective roof is straightforward. You will need a straight shot from your soffits to the ridge. That’s rather straightforward over a gable roof with no dormers or skylights, but Should the geometry within your roof is challenging — with characteristics like hips, valleys, and dormers — it’s not possible to assure air stream by means of all of your current rafter bays.
Martin, re: altering the attic more than the next Tale bedrooms to the conditioned attic and sealing the soffit vents.... Just before this latest strategy about insulating with rigid foam in addition to the cathedral ceiling, we had been intending to Reduce a ridge vent to the gable ridge, to be able to meet up with ventilation code needs. At present we have eave vents moreover two quite useless gable vents, one on both sides.
Lots of spray foam roofing contractors within our industry are touting their capability improve performance on outdated sizzling tar and graveled flat roofs by adding 3 to four inches of closed mobile spray foam. A large number of previous homes are flat roofs joisted with dimensional lumber, with parapets and also have stucco vents Lower into your rim joists.
Your caveat is appropriate and conservative. With the vast majority of builders, on the other hand, the code demands will maintain roofs freed from troubles.
I looked at the unvented schematics and I'm not sure that matches the Invoice for up listed here (Canada - west coast).
I feel you mean this: Your cathedral ceiling is presently uninsulated. If you are indoors searching up, you are able to see your rafters. Previously mentioned the rafters you can see a layer of boards. Is the fact that correct?
Many thanks for the input. I see a take a look at by using a structural engineer and 35 sq. of polyiso in my close to long run.
The roof appears to have a layer of asphalt shingles around the sheathing which has a tin roof above that. The soffits are closed off. Your house is way off the crushed route and It really is tricky to get any contractors available to work, let alone provide bids so I am virtually on my own.
In the alternative, if we won't do a ventless roof that way, can we realize our whole insulation requires by combining the above and below deck R-Values if we major everything having a vented about-roof? Thanks for your time and effort and also your information! Dan
If you'd like to set up a combination of rigid foam i thought about this on top of your roof sheathing and air-permeable insulation amongst your rafters, you must make certain that your rigid foam is thick plenty of to maintain your roof sheathing previously mentioned the dew point.
Re: the air barrier to be put over the pine T&G ceiling and beneath the foam, would you recommend that we use something that's each an air barrier in addition to a vapor barrier? Or can it be crucial to make sure that the products we pick will not be a vapor barrier, to ensure any moisture that will get into the roof assembly can dry to the inside?
Why not merely do it appropriate additionally Make with stress addressed roof sheathing. Even conventional plywood can tackle wetting cycles again and again over our number 1 super affordable OSB.
For your roof assembly over the cathedral ceiling, does the stack-up down below capture all The weather I would wish? 2x8 pine T&G (presently set up, stays because the finish ceiling)