Q: I am renovating and old home with an uninsulated, non-vented walk up attic built in 1848. The shingle roof is less than 10 years old. The simple gable roof has 2x6 rafters. I’d like to apply 2 in. of closed-cell foam and then install 3 ½ in. of R-15 rockwool and add an Intello “smart” vapor retarder. The finished ceiling will be1/2” nickel gap shiplap. Will this approach … [Read more...] about Combining Foam & Fiber Insulation in Cathedral Ceiling (Flash & Batt)
How to Prevent Condensation in Cathedral Ceiling?
Q: I’m currently dealing with insulating a cathedral ceiling, which has become a major issue. I’ve been researching solutions but feel stuck in figuring out what’s the best way to go about dealing with the problem. I have a shed roof with 2:12 pitch, built with 2x8 roof joists. It’s a mobile home that’s 14x76, so the roof is just one continuous slope. I live in northern … [Read more...] about How to Prevent Condensation in Cathedral Ceiling?
Insulating A Cathedral Ceiling With Foam Board
Q: What is the best way to insulate an unvented cathedral ceiling in a detached workshop? I plan to insulate before installing an AC and heating system (thinking mini-split). Is closed-cell spray foam the best, or only, good option in this case? I don't plan on finishing the space with drywall, although wouldn't rule it out in the future. .And given that it's only a workshop … [Read more...] about Insulating A Cathedral Ceiling With Foam Board
Air-Sealing An Unvented Cathedral Ceiling
Q: We live in Kingston, NY and cathedral ceilinged the main living space of our 1925 raised ranch. The rafters are 2×6's. we used R-21 fiberglass batts (5 1/2 " thick) and 1" pine tongue and groove boards. The roof is an unvented shingle roof. Is there an affordable solution to prevent humidity build up? – Kate A: In cold climates, unvented roof cavities can lead to moisture … [Read more...] about Air-Sealing An Unvented Cathedral Ceiling
Spray Foam For Unvented Cathedral Ceilings
John asks: Is it better to use Icynene (open-cell) or closed-cell spray foam in an unvented cathedral ceiling? We are building a new home in Atlanta, GA. Steve Bliss, of BuildingAdvisor.com, responds: I don't really like unvented cathedral ceilings, also called "hot roofs", because they are very unforgiving. If the roof sheathing or rafters ever gets wet from a roof leak, or … [Read more...] about Spray Foam For Unvented Cathedral Ceilings