Q. "If I execute the unvented roof as intended and put four inches of polysio about the roof deck, can I then use open-cell foam concerning the rafters?"
When you go ahead along with your program, you should include things like a sensible vapor retarder on the interior side of your assembly, to attenuate the transportation of humidity from the interior into the sheathing.
If you’re developing a new household, having said that, in this article’s my guidance: if you'd like to insulate with cellulose, help it become a ventilated roof by which includes air flow channels beneath your roof sheathing. Leaving out the ventilation channels is dangerous.
I've insulated the edges with R-19 fiberglass and now I am asking yourself: was that a error? It's got craft paper and I had been organizing over a plastic sheet too, should really I skip that?
To adjust to the code -- and to undertake a making technique that is certainly significantly less risky -- you need to either include ventilation channels or you must set up a layer of spray foam to the underside from the roof sheathing, adhering to the recommendations discussed during the posting on this page.
Can I get some more commentary over the "total roof" of Ice & H2o Shield? I do think this experienced little to carry out Along with the failure. The main reason why I check with is I have an analogous "whole roof" design arising, Having said that, the rafter bays are all straight runs with soffit vents, steady vent baffles (one/2" plywood) and constant ridge vent. Dense pack cellulose, two" XPS under 2x10's, air restricted drywall (XPS may very well be sealed up as well).
The correct solution to commence is to install rigid foam above the roof sheathing. There actually usually are not two responses to this dilemma. Time to accomplish the get the job done is now. When your contractor will never complete the required perform, you'll need to rent a different contractor.
A. There exists a code need for a vapor retarder in some types of assemblies, but there's no prerequisite for just a vapor barrier. Your layer of rigid foam is previously a vapor retarder. No even further vapor retarding layer need to be put in.
I've previously insulated the steep sides of my unvented mansard roof with 6" fiberglass (And that i experienced it inspected), do you suggest I rip that out and use spray or board foam? I have gotten conflicting info on regardless of whether to take care of it like a wall or a roof.
I am performing precisely the same depth on my new development. I purchased the insulation from David Volpe @ NationwideFoam.com. There is a place in Framingham, MA. I purchased various tractor trailer masses to insulate my dwelling and barn for a really, quite realistic selling price.
You may use Ice & Water Defend as an air barrier If you'd like. But when you end up picking to employ that merchandise, you'll have to news get rid of the asphalt felt so the Ice & Water Shield is usually adhered towards the roof boards.
You're describing a cathedral ceiling that comes with all possible faults. There was no attention to air sealing. The worst doable insulation was used (fiberglass). Along with the roof assembly is unvented. So it is actually no shock you are observing condensation.
Your blogs on this subject matter have already been particularly valuable and I take pleasure in your assistance. ( I do research before I submit thoughts : )
I'm opening up my dwelling and setting up cathedral ceilings, I just wanted to confirm my approach given that I received next thoughts reading through A growing number of over it. My unique choice was to go along with a vented roof system and R38C batts. I read through quite a bit about the several techniques and it nonetheless appears to me that this is the greatest. Livint in Atlanta GA We've to deal with both warm humid summers and cold winters, so humidity Handle is a challenge, This is exactly why I feel the vented strategy is the best. Anyhow, I am all the way down to the rafters and roofdecking and furred out the prevailing 2x6 with six" metallic studs, so I've about eleven.five" for insulation. Mt program was to make a steady ventilation under the roofdeck, my dilemma goes to to utilize baffles, xps board Make baffles or insect display screen nailed at furring strips to allow for that airspace.