As outlined by part R806.three in the 2006 International Residential Code (IRC), “A minimum of a one-inch Room shall be offered concerning the insulation as well as roof sheathing and at The placement in the vent.†Such a vent House can be produced by putting in one inch by one inch “sticks†in the higher corners of each and every rafter bay, followed by stiff cardboard, slim plywood, OSB, fiberboard sheathing, or panels of rigid foam insulation.
Q. "Due to the fact I am installing from above would one thing like stabilized cellulose work since it has slightly drinking water added? I'd picture loose fill could blow everywhere in the community!"
Many thanks for the confirmation and suggestions. Considering that almost everything is dry this time of 12 months and the home was just lately tented for termites, I'll insulate with the beam and seal up the plain air entryways. Once I can see inside I believe I am going to have a much better notion how much moisture is in there through the years.
It appears if a single were to work with dense pack cellulose inside of a vented cathedral ceiling the vent channel material should be rigid more than enough to face up to the tension.
I agree with you: I'd want to see more info on this issue. I'm not aware about any failures that have transpired in properly dense-packed unventilated rafter bays.
The primary vent baffles to strike the marketplace — the vintage Appropriate-Vent with the 1970s and ’80s — had been economical, flimsy products fabricated from skinny polystyrene. Polystyrene baffles have several shortcomings: being thin and flexible, they might’t resist the pressures from dense-packed cellulose or blown-in fiberglass; they don’t ventilate your complete width of your rafter bay; and as commonly mounted, they permit air to leak out the best in the insulated assembly.
one. It is best to get an engineer To judge the protection of one's 2x4 rafters. "Furring down with 2x2s" isn't going to Increase the ability of your 2x4s to bear the snow load. It can be probable that an engineer will suggest you to sister 2x8s or go right here 2x10s on to your present 2x4 rafters.
Almost all of the information I operate throughout appears to be through the cellulose field that promises wind-clean is a big issue with fiberglass; and from your fiberglass market which asserts that the cellulose group overstates the issue Which to the extent wind-wash happens it is actually inconsequential.
You're proposing a vented roof assembly. To get a vented roof assembly, the code won't require that any foam insulation be placed in direct contact with your roof sheathing -- Quite the opposite.
Our Cost of Living Calculator is a robust Resource which will help you make significant daily life decisions. Listed here are just some inquiries our calculator can solution, whether or not you might be going, modifying or starting off a occupation or simply Checking out the info:
As I explained during the post on this site, you can't use fluffy (air-permeable) insulation within an unvented roof assembly Unless of course you involve rigid foam or spray foam higher than the fluffy insulation.
I believe you mean this: Your cathedral ceiling is presently uninsulated. When you find yourself indoors seeking up, you are able to see your rafters. Higher than the rafters you may see a layer of boards. Is that accurate?
You explain your proposed air barrier as "taped felt." I do not Assume asphalt felt might be successfully taped, and I don't believe asphalt felt would make a very good air barrier.
This can be an alternative I am thinking about in my property to save lots of the prior house owners newly installed roof shingles, though the depth with the rafters can't accomodate enough insulation to satisfy code. I am wanting to know if I should furr out the rafters for getting the desired thickness of spray foam, or if installing several inches of polyiso foam on the underside of your rafters, once the spray foam, could work?