I've a detail for blueskin, as being a each an air and vapour barrier, but will also it can work as a seal for that screws that keep almost everything down. In reference into the vaulted schematics on This page, it exhibits vapour/air barrier in addition to insulation, which acquired me pondering. As good as I am putting in supplies, no person is perfect, and an air leak may possibly create in between XPS seams. As soon as ANY dampness will get right down to decrease sheathing, it is match in excess of.
It is kind of achievable to layout an unvented insulated roof assembly that performs nicely, provided that you get the main points proper.
I've a lot of partitions to re-insulate, and as soon as the roof is addressed I am going to have rafter bays to insulate, and It might be helpful to obtain some insight into which sort of fiberglass provides you with what reward for its Value.
I happen to be utilizing rigid breadboard type expanded polystyrene while in the rim joists and thought the identical may be set underneath the sheathing among the rafter bays, and with any gaps sealed using a urethane spray foam including Fill and Seal. Is there a top quality which makes spray foam satisfactory and rigid foam unacceptable?
You need to consult an electrician about The ultimate way to provide your ceiling electrical containers. There are various possible options -- some obvious from the inside, and a few hidden by The brand new foam.
2. It feels like you might be working with steel beams to frame your hips. As I'm guaranteed you understand, these metal beams are thermal bridges. All insulation must be on the exterior aspect with the steel.
The correct solution to progress is to setup rigid foam previously mentioned the roof sheathing. There really aren't two answers to this question. The time to complete the perform has become. If the contractor won't carry out the mandatory work, you'll need to rent a special contractor.
If you'd like to put in a mix of closed-mobile spray-foam to the underside of the roof sheathing and air-permeable insulation in between your rafters — an strategy occasionally referred to as “flash and batt†— the constructing code requires that spray foam (or, arguably, rigid foam insulation) be “applied in direct contact with the underside of the structural roof sheathing†and which the foam insulation meet up with the necessities “laid out in Table R806.
I now recognize that stucco can't be placed on a roof, so I'll revert on the a steel roof, but still want to acquire an unvented attic. I have browse through "Developing a conditioned attic", and am nonetheless not sure regarding The simplest way to progress.
Q. "The air barrier is usually to be put earlier mentioned the pine T&G ceiling and down below the foam. Would you endorse that we use something which happens to be both equally an air barrier and also a vapor barrier?
Martin, thanks to your fantastic and well timed guidance, we at the moment are headed toward an answer of rigid foam above the exterior in the ceiling. Thanks for pointing me Within this new and enhanced path. We remain Functioning out some aspects, for instance...
I see the recommendation is the fact that when setting up with board sheathing, one need to location a watertight membrane about the sheathing prior to installing the lowest layer of foam. Nevertheless, in my circumstance the roofer has now accomplished placing new felt around the T&G board ceiling/roof deck. Can that felt substitute to the prescribed watertight membrane, in this article in San Jose/Local climate Zone 3?
Due to their unscientific origins, code prerequisites for venting roofs in many cases are misunderstood. It’s really worth setting up a handful of fundamental specifics:
Can we (does the code permit it)? Will it make useful feeling? Are there pitfalls due to our local weather? How might We've got to modify that to fit it to over here out problem?