In some cases, these air flow channels are set up previously mentioned a layer or two of rigid foam. It’s also feasible to purchase nailbase (a kind of SIP with OSB on one facet instead of two) that features integrated ventilation channels involving the OSB and also the rigid foam; a person brand of such panels is Amazing-Vent from Hunter Panels.
I am designing a house and we are applying cellulose in 2x12 roof rafters, And that i discovered an item that seemed terrific. It really is an insulated nailbase termed Cool-Vent by Hunter Panels. It offers as much as twenty five.six R-value in foam insulation (in thicknesses nearly six" which include a one" airspace and plywood) whilst giving a cooling vent under the shingles, and straightforward set up to the roofing With all the nailbase.
Incredibly beneficial (five*) thread. So, if it's essential to use fiberglass insulation batts, so you dont have usage of spray foam or closed mobile boards, what do you need to do? I assume The important thing is to really make it unvented and insert in other air-impermeable layers. I am going to insulate a new all-metallic cathedral pitched gable roof in the Caribean. The system will be to fill the cavity between the four" Z-purlins with R-eleven batting (vapor side going through the living Area). For extra warmth conduction resistance we intend to roll Yet another thinner (filleted?) layer of this batting excessive of the purlins (ie involving the purlins as well as sheeting).
Q. "If I execute the unvented roof as developed and set 4 inches of polysio around the roof deck, can I then use open up-mobile foam involving the rafters?"
Am i able to get some far more commentary about the "entire roof" of Ice & Water Defend? I believe this experienced very little to try and do Using the failure. The explanation why I request is I have a similar "entire roof" style developing, Having said that, the rafter bays are all straight runs with soffit vents, continual vent baffles (one/two" plywood) and constant ridge vent. Dense pack cellulose, two" XPS beneath 2x10's, air tight drywall (XPS could possibly be sealed up way too).
You happen to be describing a cathedral ceiling that comes with all attainable errors. There was no interest to air sealing. The worst achievable insulation was utilised (fiberglass). As well as the roof assembly is unvented. So it truly is no shock that you're seeing condensation.
This post was Very beneficial, Thank you! I have a single query about making a vented assembly by earning an airtght process with accuvents.
Set up closed-cell spray foam towards the underside with the roof sheathing, and no other style of insulation. Make certain that the thickness on the spray foam is adequate to fulfill minimum amount code specifications. Take into have a peek at this website account that open-cell spray foam is risky in all local weather zones, and if open up-cell spray foam is set up in this locale in a cold weather, the underside of the cured foam needs to be included with gypsum drywall that's been painted with vapor-retarder paint. Vapor-retarder paint is ineffective if it is sprayed instantly within the cured foam.
I see the advice is the fact when commencing with board sheathing, just one must position a watertight membrane in excess of the sheathing just before putting in the bottom layer of froth. Nonetheless, in my circumstance the roofer has previously finished inserting new felt in excess of the T&G board ceiling/roof deck. Can that felt substitute for that prescribed watertight membrane, in this article in San Jose/Local weather Zone three?
This article will go over insulated sloped roofs. The strategies explained right here can be used to make an insulated cathedral ceiling in excess of an awesome space, a bit of sloped roof higher than a kneewall, or any very similar area of insulated sloped roof.
If you are doing as you suggest, you would probably attain an addition take advantage of the R-20 insulation higher than the roof sheathing. That said, the method you describe would not satisfy code necessities For brand spanking new construction, mainly because ideally any insulation accustomed to dietary supplement the rigid foam over the roof sheathing ought to be in direct contact with the underside of your roof sheathing.
If it looks like I'm out of my depth in this article... yeah, you guess, I'm. I am simply a homeowner, with only some days of Online research below my belt. Nevertheless the contractor is just not aware of this roofing technique, so we are needing to determine it out alongside one another. Take pleasure in your enable immensely.
Q. "If I change the felt with Ice & H2o Protect or the same asphalt-dependent solution, I would in all probability just be leaping from your fireplace into the frying pan, odorwise. This really is main me to imagine that the Solitex or Delta goods could be greater."
Most rafters aren’t deep plenty of to accommodate the insulation required to meet up with minimum R-values required by code, particularly if the rafter bays include things like a air flow channel.