A. You ought to only use an installation system that the insulation contractor is familiar with. In this article in the Northeast, many contractors would almost certainly fill your rafter bays utilizing the dense-pack system following your new roof sheathing was set up.
We had a Zip Roof set up and a metal Roof positioned in excess of it. The roof assembly is just not vented and taped all throughout the soffits. Preferably I would like to pack your complete cavity with blown cellulose. This string of discussions is offering me pause for imagined.
I used to be skeptical of Invoice Hulstrunk's claim that AccuVent baffles could withstand staying dense-packed in an enclosed cavity.
Thanks Martin - Now I see why my primary plan for a SIPS envelope was so elegantly basic. It looks like min R-10 sprayed beneath the roof sheathing and afterwards a full-fill of your bays with batt / fluffy, in addition to a vapor sealed drywall lid can get me the 'incredibly hot' (unvented) roof method the SIPS was from the get go.
Utilizing ventilated nailbase panels is a perfectly good way to make a cathedral ceiling. The exact same policies apply as when making use of SIPs: make certain that the seams are sealed to get as airtight as you may make them, and make certain that the whole R-value of your roof assembly fulfills or exceeds bare minimum code R-price needs.
Most of the knowledge I run throughout appears to be through the cellulose industry that promises wind-wash is a major challenge with fiberglass; and with the fiberglass business which asserts which the cellulose group overstates The problem and that on the extent wind-clean occurs it is de facto inconsequential.
If you want to build an unvented insulated roof assembly, you almost certainly don't want to disturb the tile roofing. That means look at here now that essentially the most suitable insulation could well be spray polyurethane foam. Certainly, the present insulation must be eradicated ahead of you install the spray foam.
Even though the GBA Internet site presently has a lot of articles or blog posts on the topic, we continue to receive Regular questions on The obvious way to insulate a cathedral ceiling.
 To all of my kin, pals, and neighbors thanks for your aid and problem with the many excellent food stuff, cards and type terms.
It is sensible to be sure the best layer of sheathing can dry to the exterior when employing rigid insulation on an unvented cathedral ceiling. But How about the proposed water-resistant underlayment for valleys, eaves, and minimal-slope sections of roof?
Element D: Either notch the treated 2x4 spacers for fitting 1x4's horizontally throughout them to be able to ...Portion E: Install metallic roof around this.
I have plenty of walls to re-insulate, and once the roof is dealt with I am going to have rafter bays to insulate, and It will be handy to possess some Perception into which type of fiberglass will give you what benefit for its Expense.
Problem comparable to Eric, earlier mentioned. If shut cell foam is sprayed or "cobbled" from xps, do You need to fill the whole House, or only to thickness for ideal R worth?
Thanks for your opinions. We will never A/C the setting up (It will likely be solar run). The wind is really constant, but it's a humid environment, so humidity control is certainly on my intellect.