Insulation for my basement walls
Hey,
Was wondering if anyone could recommend a type or place to get rigid foam for my basement walls.
The price of rigid foam insulation seems to have skyrocketed. I have 8′ ceilings in my basement and about 70 linear feet of concrete wall to insulate. That’s 35 2×8 sheets of dow XPS which at $42 a piece is $1600-1700 for r10. Throw Roxul on top of that to get to r24 and now I’m looking at $2500 for just insulation.
I know that you need 2″ for the foam to act as a vapour barrier. But with 1″ being significantly cheaper, is it acceptable to do 1″ against the wall and then just put a poly around the batts and frame?
I could get 2″ EPS for even cheaper than 1″ XPS. Is this a better option?
Last thing I’m wondering is if it’s also necessary to do 1″ on my concrete floors. I found that my slab is actually insulated with foam under the top slab. Would this maybe mean I don’t need 1″ foam on top as well?
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Replies
Tim,
Q. "I was wondering if anyone could recommend a type or place to get rigid foam for my basement walls."
A. Craig's List. You're looking for "reclaimed rigid foam" or "recycled rigid foam."
Q. "I found that my slab is actually insulated with foam under the top slab. Would this maybe mean I don't need 1 inch of foam on top as well?"
A. Yes. In most cases, if you have a continuous horizontal layer of rigid foam under your slab, you don't have to add more rigid foam above your slab. That said, it would be helpful to know (a) your Climate Zone or geographical location, and (b) the type and thickness of rigid foam that is now underneath your slab.
I usually only use the search terms | rigid insulation | when looking for it on craigslist or online.
Including "reclaimed" or "recycled" gets fewer hits, "foam" often gets hits for things other than sheets of insulation.
eg:
https://boston.craigslist.org/search/sss?query=rigid+insulation
vs.
https://boston.craigslist.org/search/sss?query=reclaimed+rigid+foam
vs.
https://boston.craigslist.org/search/sss?query=recycled+rigid+foam
vs.
https://boston.craigslist.org/search/sss?query=foam+insulation
Thanks, Dana, for the helpful suggestions.