Im in Ontario, GTA. So zone 5, is 4” inch white EPS enough ?
Maxxxx001
| Posted in General Questions on
Hello,
Planning on finishing a basement, thinking about using 4” EPS boards and leaving stud cavities open.
I will be using steel studs.
On the same note steel track should I first place an 1” of EPS under the track? Or just a thin foam seal is enough?
Thank you
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Hi Max,
I have asked several questions and not gotten answers, usually because I didn't do a proper search first. The link below should answer most of the questions you will have about assembly. You will need to check your local code to know required R-values etc. Typically EPS will have an R-value of +/= R3.85 per inch so 4-inches will be about R-15.4.
https://www.greenbuildingadvisor.com/article/how-to-insulate-a-basement-wall
2x4 steel studs with 3.5" of EPS is going to give you an effective insulation value of about R-4, at best. I think there's a consensus that insulating the cavities between steel studs is rarely worth it. You'd get about as much total R-value by placing 1" of insulation behind the stud wall.
A thin foam seal under the track will provide a vapour barrier, but not much in the way of R-value. Perhaps R0.5, depending on exactly how thin it is.
Trevor,
The foam is to be continuous, and the stud cavities empty.
Yes, I'm not sure how I misread that.
Trevor,
I misread questions all the time, but I'm sneaky enough I edit my response to hide it.
There are specific products out there on the market to do this ...
"Unlike traditional wood framed walls and insulation, InSoFast panels will never be damaged by moisture, rust rot or decay. It’s a simple, installer-friendly system that requires ZERO building skills to achieve quality, professional insulation and framing in a fraction of the time."
https://www.insofast.com/insofast-products-applications/insofast-interior-applications/interior-uses
I've used Insofast on small projects.
The original product is R8, which only meets code in Zone 3 and below. The have a 3" product for zone 4 and a 3.5" product for zones 5 and up.
The R10 product is about $3.50 per square foot. For anything other than small areas that's really expensive.
Maxxxx001,
The 4" of EPS will be sufficient to keep the wall safe, but I believe Ontario revised its energy code in 2021, and I don't know what the new levels for basement insulation are.
Hello,
Thank you for answers!
I’m going with 4” EPS type 2 with R Value that will give me R16.6, code calls for R20
I will put studs over EPS and leave them empty, as per forum recommendation’s.
I currently have R20 fiberglass with Poly over it ( builder special ) I think my R16 EPS will be superior.
As for the bottom metal track, I guess I will go ahead and use 2” XPS and track over it, or use the foam seal and 2x4 and nail track to that, to avoid thermal bridging
One thing I would like to confirm is the seal sealer under bottom plate as well as continous foam per diagram in the post on how to insulate basement walls ? Is that correct ?
I was going to run eps to floor and caulk bottom
Thank you
Friends !
I was going to rigid and batt my basement with 2" rigid and fiberglass in the 2x4 cavities. The rim joists were to be 2lb spray foam. It was actually faster and just as cost effective to have them spray closed cell behind the stud wall. The closed cell also ends any debate with an inspector if there is an adequate vapor barrier. Ontario still loves poly.