How does this seek out a system? Nearly anything you'd probably change/insert/reorder? Do you agree with taping the seams in both of those layers of plywood?
If you want to build an unvented insulated roof assembly, you've got two possibilities: (a) You can incorporate rigid foam to the exterior facet of your roof sheathing, followed by a 2nd layer of roof sheathing and new roofing, or (b) You could insulate the underside of the roof sheathing with spray polyurethane foam.
Many thanks with the suggestions. We won't ever A/C the constructing (It will likely be solar run). The wind is fairly regular, however it is a humid atmosphere, so humidity Management is surely on my mind.
Also, why not zip panels taped and after that roxul batts with drywall more than that. Roxul is wonderful things I are actually screening For several years in ridiculous approaches wanting to see its abilities. I believe that zip panels, taped thoroughly, with roxul batts will very last given that the roof!
I'm a homeowner in Seattle. Have a freshly-framed, vented cathedral ceiling to insulate. Straight bays, 2x12, 24" o/c. The current approach is to make use of batts of some variety during the bays, acquire treatment to air seal the inside surface, stay clear of penetrations, air seal the vent channel as well (bays fully sealed), double primary The within area for vapor resistance. I have a couple questions about baffling the vent channel: one. A lot of the making specialists I am dealing with sense the jury remains out on baffles and so are recommending leaving the batts open up to your channel apart from near the vents, assuming the one-2" air channel may be taken care of.
Insulated cathedral ceilings are a relatively current phenomenon. The fad for insulated cathedral ceilings (and wonderful rooms) truly took off in the nineteen seventies and eighties, when illustrations commenced popping up like mushrooms after a heat rain.
Doug I agree, a lot of wrongs "overthinking" and overdoing. I at the time had to resupply a physician building an plane with dozens of AN plane bolts mainly because they had been tightened to the point of breaking the bolts. Considerably less is more from time to time... Along with the KISS rule.
Set up closed-mobile spray foam against the underside of the roof sheathing, and no other sort of insulation. Ensure that the thickness from the spray foam is suitable to satisfy minimal code necessities. Remember that open up-cell spray foam is dangerous in all local climate zones, and when open-mobile spray foam is mounted In this particular location in a chilly local climate, the underside of your cured foam has to be included with gypsum drywall that has been painted with vapor-retarder paint. Vapor-retarder paint is ineffective if it is sprayed straight around the cured foam.
Your proposed assembly can be a code violation. If you want an unvented roof assembly, you must continue to keep the roof sheathing heat with spray foam or rigid foam. Cellulose insulation is classified as an air-permeable insulation and can't be Utilized in this kind of roof assembly.
Hence the issue is: seal the stucco vents original site and incorporate the spray foam roof and Don't fret about condensation? There exists very little small-hanging fruit in our sort of design, In particular on existing houses, And that's why men and women are currently being sucked in to the spray foam roof scam.
Martin, thanks. I just talked into the roofer and he rejected the thought of only Placing the foam more than the spouse and children space cathedral ceiling. That Bizarre "jog" from the roofline, possessing it instantly bump up four" or eight" exactly where the household place commences, in the midst of the back again side with the roof, would defeat the thought of a ongoing slope for rain to come back down when it hits the higher Component of that back again roof. So the 4" or 8" height addition requires to carry on through the entire 2nd Tale roof line.
A. The polyiso will never create a mould challenge. While you're appropriate that black going through won't provide a radiant barrier, the difference in performance in comparison to foil-confronted polyiso will be minor.
Beneath the 2x8 pine T&G, There's 9" of beam exposed, but we have only four” or within the very utmost five” to Engage in with, due to the fact at the highest from the stairs which ascend the aspect from the space, the ceiling is hardly higher than a tall individual’s head as it really is. On top of that, we would like to take care of an uncovered beam profile for your aesthetics. I hope the attached images illustrate your situation. I feel an unvented roof assembly is the one chance here, as the very best issue of your cathedral ceiling isn't the ridge in the roof.
Q. "If I install a polyethlene sheet amongst The underside of the batting and the sheetrock [it would be connected into the purlins], would not this be an interior vapor barrier?"