New Basement ICF vs interior spray foam
On to the basement. I was planning to use ICF but after carefull reading of a building science article on the topic I am having second thoughts.
http://www.buildingscience.com/documents/reports/rr-1003-building-america-high-r-foundations-case-study-analysis
I need a finshed basement with finished walls, electrical etc. Case 13 in the document above describes an ICF assembly with R10 out, R10 in and R10 under slab. I assume I would then need a 2×3 or 2×4 wall anyway on the interior to run electircal (not sure if this is a correct) unless you somehow can run the wiring right in the ICF assembly itself. Consider this vs a ‘regular’ concreted wall also with R10 under slab but finished on the interior with a 2×4 wall standing off an inch from the concrete and then cavity filled with closed cell spray foam and finished with drywall (case 6). I’m struggling to see the benefit of ICF at this point… Any thoughts?
Thanks.
Replies
You only need 1.25" from the
You only need 1.25" from the FACE of the drywall to the wire. You just make a slot in the foam to accomodate the wire. You could also run conduit.
An ICF wall is simple easy to build. Either fur out from the ICF or install conduit inside the ICF's before placing the concrete. Conduit is actually rather easy once you get the hang of it. And conduit allows for future changes.
Cost?
I don't know what your budget is. but i faced the same conundrum. We are required to have an R-5 on the outside of a foundation wall, so ICF looked like it would give me a head start for both interior and exterior insulations. However after crunching the numbers and 8" poured wall with 1" rigid foam applied outside and 1" also applied inside was more cost effective. I then used a standard 2x4 frame wall inside and will used either sprayed cellulose or dense pack cellulose. Since I'm in a mixed heating/cooling climate I chose not to use a vp inside, thuse allowing the walls to dry to the inside. Outside I used Rub-R-Wall as my foundation water proofing (thus far it has also acted as a bug deterent too, along with normal chemical treatment).
Remeber, there are LOTS of ICF products on the market. Some accomodate wiring channels and drwall attachment built into them (I think good ones should) ... You should NOT have to fur in to drywall. Explore your ICF options before assuming it will leave you a little bit kooked in the interior finish department.