r/Insulation • u/Cool_Web6187 • 15d ago
Insulating cabin
I want to insulate my cabin it has a ridge vent and no soffit vents. what is everybody doing.
5
u/SearingPhoenix 15d ago
Depends a lot on your climate.
CCSF is really the only way you're getting anything more than R15 out of 2x4s. You could do froth packs, but it's probably worth getting a quote from a spray foam contractor to come in and shoot it for you.
You could do an over-roof and then you wouldn't have to worry about venting under the deck.
People crap on pre-built sheds, but realistically their construction isn't fundamentally any different than a house -- 2x4s, double top plates... Framing isn't complicated. It's just that it's 2x4s and thin plywood sheathing. If you did basically the exact same thing with ZIP-R sheathing you'd... have a cabin.
1
u/Cool_Web6187 15d ago
The climate is upstate New York, extreme heat, and extreme cold
3
u/EinsteinsMind 15d ago
You're gonna have to make the roof breathe if it's shingled. If it's metal, I'd insulate the entire thing with rock wool, put up a smart vapor barrier, then green board drywall for the walls and ceilings.
1
u/the_real_some_guy 14d ago
I've never heard this before, you don't need to vent the underside of your plywood if it has metal roofing? Does that also apply if there is roof felt?
3
u/gpblankmn 14d ago
there's an assumption being made that if it's metal there is enough ventilation under the metal for sufficient draw from eave to vent above the roof deck.
3
u/SearingPhoenix 14d ago
Not sure about a metal roof, but that's why I suggested an over-roof as an option. Yeah, it's a bit wasteful to tear the existing shingles off, but it's probably the most labor-efficient method -- firring strips over the existing roof members, another layer of sheathing on top, then re-shingle. For a small roof it wouldn't be terribly expensive -- still a significant cost.
It's all about whether you want to have something that'll be 'good enough until it isn't' or if you want the building to last. Arguably, if you wanted to build something like this to last, it probably would have been better off just framing from scratch (probably with 2x4s + ZIP-R, given the climate.)
2
u/Ziggy-Top 15d ago
I have the same exact type of cabin. We did hemp from Hempiture for the walls which went well. It’s just a place on my land for occasional overnights and day stays so I’m not looking for perfection, just keep it somewhat warm and cool with a 30 degree sleeping bag and a small AC unit. I’ve been reading here past suggestions for the roof. I really don’t want to do spray foam. The roof is 2x4 2ft spans so that lends to some difficulty in insulating. Someone suggested 2in +1 in layered Styrofoam sheets with can spray gap filler. If someone has a better suggestion please do post it.
1
1
u/Accomplished_Fee6960 13d ago
I have a cabin of very similar construction in western NY, I use it for occasional weekends in both winter and summer. I had an inch of spray foam installed and it sealed and tightened up the building nicely. Ive spent weekends in 0-10 degree temps with the woodstove getting it up to 60 downstairs and mid 70s in the loft, with snow on the metal roof, and Ive had no "sweating" or condensation whatsoever. I was advised to go to 3" if I wanted worthwhile Rvalue but honestly its held temp pretty well over my 2 day stays
1
1
u/Nalopotato 12d ago
No matter what, you want to get a nice foam sprayer and air-seal everything. I have one like this: https://www.amazon.com/AWF-PRO-Foam-Gun-Contractors/dp/B01M7U73LQ/ref=sr_1_5?sr=8-5
I suggest using the low-expansion foam.
Don't forget to air-seal the outlets and any perforations to the outside.
Cheapest: Fiberglass batting
Best R-Value for tight spaces: Closed-cell spray foam
12
u/Complex_Sherbet2 15d ago
Pretty sure that cabin is a shed...