dampness to move out of your ceiling. The point is to test to take care of any moisture that makes its way there Despite
Q. "I'm wondering if I should really furr out the rafters to acquire the desired thickness of spray foam, or if installing several inches of polyiso foam to the underside in the rafters, following the spray foam, could do the job?"
Below the 2x8 pine T&G, there is 9" of beam exposed, but we only have 4†or in the extremely highest 5†to Participate in with, because at the best from the stairs which ascend the side of the place, the ceiling is scarcely higher than a tall individual’s head as it really is. In addition, we want to take care of an uncovered beam profile to the aesthetics. I hope the attached photos illustrate your situation. I feel an unvented roof assembly is the only chance here, as the best issue of the cathedral ceiling isn't the ridge in the roof.
I must speculate In the event the failure inside the Picture would have occured In the event the hip and ridge was vented and every little thing else the identical?
In order to choose a cloth that is definitely a bit far more vapor-permeable for the air flow baffle, it is possible to -- as an example, lots of people use skinny plywood or fiberboard in this area -- but you truly do not have to. The EPS will work
The initial vent baffles to strike the marketplace — the vintage Suitable-Vent of your nineteen seventies and ’80s — were affordable, flimsy items manufactured from thin polystyrene. Polystyrene baffles have many cons: remaining skinny and flexible, they will’t resist the pressures from dense-packed cellulose or blown-in fiberglass; they don’t ventilate the complete width of your rafter bay; and as commonly mounted, they allow air to leak out the top of the insulated assembly.
Outstanding write-up and dialogue. I have a question about an existing unvented attic assembly. The rafters are 2x4's and also the bays concerning them are fully full of shut mobile spray foam. I wish to increase two 1in levels of polyiso toward the interior of attic after which you can go over with a vapor open up membrane to airseal the assembly.
Amazingly beneficial (5*) thread. So, if you will need to use fiberglass insulation batts, therefore you dont have usage of spray foam or shut mobile boards, what do you do? I suppose The main element is to really make it unvented and insert in other air-impermeable levels. I am about to insulate a different all-steel cathedral pitched gable roof within the Caribean. The program will be to fill the cavity among the four" Z-purlins with R-eleven batting (vapor aspect facing the dwelling more information Room). For additional warmth conduction resistance we plan to roll One more thinner (filleted?) layer of this batting excessive on the purlins (ie among the purlins and the sheeting).
The roof appears to possess a layer of asphalt shingles above the sheathing using a tin roof above that. The soffits are shut off. The house is way from the overwhelmed path and It is really hard to get any contractors in existence to operate, let alone provide bids so I'm pretty much on my own.
I similar to the detail presented but I would not phone that a cathedral ceiling ailment mainly because it contains ceiling joists spanning at the bottom of the roof rafters. I'd connect with this an insulated attic.
As the head of our regional HBA, I have strenuously identified that foam above a vented flat roof assembly does not provide the insulation values promised. Some builders have recommended they might merely seal and stucco over the stucco vents and do away with the ventilation.
As for my Electrical power auditor recommending blowing cellulose into your mansard sides, you also recommend versus that? I was underneath the perception blown cellulose prevents humidity migration.
Recall: Simply because your roof assembly is dry, doesn't mean it is effectively insulated. Your assembly could have significant air leaks that work as thermal bypasses. (Or not. It is tough to convey to without a website visit.)
(d) There may be adequate air leakage on the "soffit" and ridge to supply air flow that functions how a ventilation hole ordinarily would.