A. There's a code prerequisite for your vapor retarder in certain kinds of assemblies, but there is no need for a vapor barrier. Your layer of rigid foam is now a vapor retarder. No even more vapor retarding layer should be set up.
Okay, I was figuring that the overall with the rigid foam + cellulose needed to be a specific R-worth together and had been thinking of employing a lot less rigid foam. I have been looking through about different types of cellulose. Considering that I am installing from previously mentioned would anything like stabilized cellulose work because it has a little h2o extra?
Are you currently wondering the 'flat' vented cavities will not likely give the assembly by having an exhaust route for dampness?
A. To make use of the insulating worth of the rigid foam about the attic, you surely choose to seal up any attic vents, so you unquestionably don't need to create a ridge vent.
I now sprayed and Slash cobbled 4 inch of closed mobile. I'll redo the roof following yr, but I guess now it is too late to consider eps/iso on top of roof given that i now unvented the attic.
Eventually, suppliers started providing stiffer options which have been much better in a position to resist the pressures of dense-packed insulation. These items arrive and go, and plenty of are no more out there.
I've a issue for blueskin, being a both an air and vapour barrier, but in addition it will eventually work as a seal for the screws that hold every little thing down. In reference into the vaulted schematics on this site, it displays vapour/air barrier along with insulation, which bought me pondering. Pretty much as good as I'm setting up supplies, nobody is ideal, and an air leak might produce in between XPS seams. At the time ANY moisture receives down to decreased sheathing, it is actually video game in excess of.
I believe that folks who write creating codes are worried that, In case the code permits unvented rafter bays to generally be insulated with cellulose, failures will official source arise as a result of sloppy cellulose installation.
Magic bullet status will not be reached. It's a design and style for your reduced slope roof. It can be a great deal along the lines of Doug McEvers use of higher perm fibre board to create vent channels earlier mentioned dense packed cellulose.
Set up closed-mobile spray foam against the underside with the roof sheathing, and no other variety of insulation. Be sure that the thickness on the spray foam is adequate to fulfill Visit This Link bare minimum code necessities. Do not forget that open-cell spray foam is dangerous in all weather zones, and when open-mobile spray foam is installed On this location in a chilly local weather, the underside from the cured foam should be coated with gypsum drywall that's been painted with vapor-retarder paint. Vapor-retarder paint is ineffective whether it is sprayed right about the cured foam.
I've an urgent problem and might be really grateful for advice on insulating our property’s loved ones home cathedral ceiling, inbuilt the 1970’s and at this time currently being re-roofed. (The aged roof continues to be torn off, and they are about to commence installing the new shingles.) The house is in San Jose, CA, weather zone three. The contractor doesn't need to place insulation above the sheathing, that's 2x8 pine tongue and groove, which up til now served as being the finish ceiling.
If you wish to install a mix of closed-cell spray-foam within the underside on the roof sheathing and air-permeable insulation in between your rafters — an method often named “flash and batt†— the building code calls for that browse around these guys spray foam (or, arguably, rigid foam insulation) be “applied in direct contact with the underside in the structural roof sheathing†and that the foam insulation satisfy the necessities “specified in Table R806.
Because a roof assembly doesn't Keep to the principles set up from the creating code or recommendations of building researchers does not imply the roof has
My view would be that the steep facet of a mansard roof is often a roof. This is often very true if the outside with the sloped assembly is completed with roofing.