Do not make any hasty decisions that you will regret. If needed, explain to your roofer to stop all Focus on this challenge until this issue is resolved (assuming, of course, that your roof sheathing is protected by asphalt felt or the same underlayment.)
Preferably, you wish to have an airtight barrier over and down below your fiberglass batts. If you're able to attain All those two air boundaries, then wind-washing is not a problem in a roof like yours. (It could be in a vented unconditioned attic, certainly, Particularly near the soffits.)
Second, are you able to make sure you verify this: "If you want to use only one form of insulation in unvented rafter bays, you might be restricted to spray polyurethane foam."
If you like, you can Find your air flow channels in addition to the roof sheathing in lieu of under the roof sheathing. If you choose to do this, Guantee that any roofing underlayment that you put in over the roof sheathing is vapor-permeable — as an example, #fifteen asphalt felt, VaproShield SlopeShield, or Solitex Mento — and that your local developing Division accepts this method of roof venting.
Sure It really is many hassle. It looks like much less problems the depth posted as case in point in the web site previously mentioned and employs no foam... That's a "biggie" for me.
Martin, Thank you for the reply. Those articles or blog posts are the two very insightful. I am receiving the perception that SIPs can be carried out properly, but could be conquer in value with exterior rigid foam techniques when you've encouraged, with equivalent or far better efficiency (with emphasis on air-tightness).
Irrespective of whether you decide to really make it vented or unvented, get the main points ideal — mainly because each and every cathedral ceiling features prospects to help make big issues
Doug... For some reason I did't see your publish #17. Appears like two of us not less than Consider there may be a very easy economical Answer.
I see your place. I this content have never worked with fiberboard. Can it be taped and thought of a reliable Key air barrier?
I am doing a similar detail on my new development. I purchased the insulation from David Volpe @ NationwideFoam.com. view it You will find a location in Framingham, MA. I bought quite a few tractor trailer loads to insulate my residence and barn for an incredibly, quite realistic rate.
I've an unfinished attic, with cathedral ceiling, no insulation right now. in 5-10years we will be including dormers, but in the meantime i want to include insulation and drywall in The best, most reversible/salvageable method. My plan is to hang two layers of two inch polyiso underneath the rafters, taped with staggered seams leaving the rafters vacant, so primarily a vented assembly. I have included blocking to the ground joists and will make the polyiso steady inside the knee partitions. I assumed i would increase furring strips on top of the insulation then cling drywall, believing that the furring strips would produce an airgap, letting the foil to work as a radiant barrier.
Another way to include R-price on your roof assembly is to incorporate one or two layers of rigid foam during the roof assembly — both earlier mentioned the roof sheathing or down below the rafters.
[Editor's Take note: Monthly bill Rose just despatched me the following reviews within an e-mail; he included his authorization to article the comments.]
Try to remember: Home Page if you end up picking to set up rigid foam on top of your roof sheathing, don’t put in air flow channels under the roof sheathing; both of these techniques are incompatible.