three. Applying continuous Ice & Water Shield is usually risky, however it's OK if you are pursuing the PERSIST approach and putting all of your current insulation on the skin with the peel-and-stick. The strategy can get the job done, but you will need a great deal more foam on the exterior of one's roof.
The program is to install it (from The within of the home) with regards to the very same time the drywall is place up. I will instruct my crew to make certain there won't be any air pockets during the purlin cavities & no air flow into your latter.
A. The air barrier might be a vapor barrier, as the rigid foam can be prone to become a vapor barrier (or near it) in almost any situation.
2. It looks like you're applying steel beams to frame your hips. As I am sure you know, these steel beams are thermal bridges. All insulation should be on the outside side from the metal.
Can I get some more commentary within the "total roof" of Ice & H2o Shield? I think this had hardly any to do Using the failure. The reason why I check with is I have an analogous "total roof" structure arising, Nonetheless, the rafter bays are all straight operates with soffit vents, continuous vent baffles (1/two" plywood) and constant ridge vent. Dense pack cellulose, two" XPS below 2x10's, air limited drywall (XPS could be sealed up too).
You should seek the advice of an electrician about The simplest way to serve your ceiling electrical containers. There are plenty of attainable solutions -- some visible from the inside, and several hidden by the new foam.
Your go to my site system to setup 8 inches of rigid foam is an efficient 1, but you may be able to put in thinner foam if there is a powerful cause to take action. Of course, 8 inches of rigid foam has an increased R-value, and can complete greater, than the usual thinner layer.
It is sensible to be certain the top layer of sheathing can dry to the exterior when using rigid insulation on an unvented cathedral ceiling. But How about the suggested watertight underlayment for valleys, eaves, and small-slope sections of roof?
Q. "You say 'You don't want an interior vapor barrier,' but You furthermore mght claim that 'You will need a fantastic air barrier on both sides of one's fiberglass batts.' The latter would turn out to be an inside vapor barrier not so?"
"When you have installed the code-mandated thickness of rigid foam earlier mentioned your roof sheathing, you’re cost-free to install as much fluffy stuff as you desire among the rafters."
The air leakage that Dana mentioned would maintain your roof dry, but would undermine its thermal functionality.
Thank you, Martin and Stephen. Fortunately we are inside a situation where we could pause and reconsider, as The brand new felt has long been put, Nonetheless they haven't started out installing shingles yet. I will explore the problem Using the contractor yet again. I might be able to get him to reconsider.
You explain your proposed air barrier as "taped felt." I don't Consider asphalt felt might be correctly taped, and I don't believe asphalt felt can make an excellent air barrier.
It's a code violation to setup an air-permeable insulation like fiberglass batts concerning unvented rafters. It is also a foul notion, for the reason that dampness can accumulate on the roof sheathing if you try this technique, and you will end up getting sheathing rot.