Any house becoming built much better than the absolute minimums need to for the incredibly the very least not use OSB for roof sheathing. Imo
As the head of our nearby HBA, I have strenuously identified that foam in excess of a vented flat roof assembly doesn't supply the insulation values promised. Some builders have instructed they may merely seal and stucco about the stucco vents and get rid of the air flow.
Well the roof is going on with the first layer of insulation (on-leading the purlins, beneath the roof sheeting). There seems to be sufficient House left during the four" purlin cavity for the next layer of R11 to be put in with none modification.
Thanks - this is new construction, I am the designer / builder, and the more I check out it, I am liking all rigid - significantly less fussy. The top layer of rigid above fluffy can make my eave as well thick anyhow. The air barrier for the T&G ceiling is actually the sandwich of felt and taped three/eight" CDX.
You should definitely install insulation that provides not less than the minimal code requirement for ceiling R-price. Insulation that exceeds the bare minimum code requirement is a lot better.
I'm building a forensic laboratory produced in Massachusetts, and am aquiring a complicated time reconciling relevant setting up code with my study of the literature pertaining to insulation and roof deck condensation.
. Unvented roof assemblies are Harmless. The main reason that a lot of people install ventilation channels over the rigid foam is simply because they are now living in parts with lots of snowfall, and they like a "cold roof" to reduce ice damming challenges. Thanks to your comment. I will edit my post to try to explain any ambiguity on this issue. .
Outstanding post and dialogue. I have a matter about an current unvented attic assembly. The rafters are 2x4's plus the bays between them are entirely stuffed with shut cell spray foam. I want to incorporate two 1in layers of polyiso toward the interior of attic and then cover having a vapor open membrane to airseal the assembly.
Thanks for the suggested addition to the listing of elements for making internet site-designed vent baffles. I have edited the text of my website to include your recommendation.
I'm such as a photo of the answer: spray foam held down from the top fringe of the rafters to ensure that air is often drawn up from soffit vents to gable vents from the truncated attic cavity.
First, many thanks Martin with the prosperity of data this Web-site has. I have been discover this checking out it often for the previous few many years, ever because acquiring my initially house. I'm also located in northern VT, zone six but I feel we could be pushing 7 because of localized conditions. I have recently experienced an Power audit executed and wanted to confirm one of the suggestions. We've got a region with a cathedral ceiling, and likewise a get rid of dormer created to the cathedral. The cathedral ceiling is insulated with r38, along with the get rid of dormer with r19. Each are kraft confronted fiberglass. The roof is 12/twelve to the cathedral, undecided but much less within the dormer, and it has snow coverage (generally more than 8") from the start of January right up until mid March.
I feel you necessarily mean this: Your cathedral ceiling is presently uninsulated. While you are indoors looking up, you may see your rafters. Higher than the rafters you'll be able to see a layer of boards. Is usually that appropriate?
one. You do not need an interior vapor barrier. Inside a warm humid climate, the vapor generate is usually from the outside towards the inside (assuming your developing is air conditioned). In case your developing isn't really ever going to be air conditioned, the vapor drive will nevertheless be from the outside to the interior, but there won't be Considerably vapor generate.
As mentioned above, we hope to replace the roof this future yr. In that case, at that time I'd like to enhance to either an unvented roof or if important a chilly roof (a vented above-roof). (I don;t realize This Site that it issues during the equations, but we are looking at acquiring and putting in stamped steel shingles.