I'm getting ready to build a 1900 sq feet home this fall. It will have a 1900 sq feet walkout basement under it. I'm going to have geothermal installed. The bid I got on that was that it would cost an additional $10,000 for a horizontal loop system. That seems like a no-brainer to me especially when factoring in the 30% tax credit. My question is would it be worth it to use ICF in the basement vs a standard concrete block foundation. The quote I have is that it would cost an additional $5500 to upgrade to ICF.

I have an ICF house, and I would never go back to frame or block

What would it cost to build with ICF all the way up? There are many advantages:

1) Insulated thermal mass
2) Superb strength of rebar and pored concrete
3) Sound reduction
4) inedible to ants / termites

Where are you building?

I don't know what it would cost to do the whole thing ICF, I've never heard of anybody doing that around here. I live in Northern Michigan. I'm sure the geothermal will be a good investment. I wasn't sure if doing the basement with ICF would be worth the additional cost. I'm not sure how that would affect my heating bill. I'm sure it would lower it but with already having geothermal, would it lower it enough to justify the extra $5500?

Joe Ami is our upper midwest guy. He can probably give you a quick guesstimate as to likely savings between the two basement options. Aside from insulation, the additional strength and integrity afforded by a monolithic pour appeals to me for a basement.

Down here our 71*F ground temperature is quite appealing year round - if someone made an R-zero concrete for slabs or basement walls we'd be well-served to use it.

Posted By jrbuch on 09 Jun 2012 04:27 PM
would it be worth it to use ICF in the basement vs a standard concrete block foundation. The quote I have is that it would cost an additional $5500 to upgrade to ICF.

ICF is almost a different product compared to CMUs, except both get you out of the dirt. You need a good foundation to build a good house. ICF to the eaves is the best...Harder to remodel
What are the ICF dimensions; how much insulation, width of concrete? If you went CMUs, would you insulate the CMUs? Insulation is built in to the ICF.
What is the depth of dirt on the uphill side
Walkout doors and windows would have deep reveals; solid looking and it is.
Monolithic pour Is appealing... Thermal Mass is a plus. Moisture issues are lessened. Dew Point issues in a wall assembly are eliminated. Run interior wires in channels cut in the foam is possible.

Plumbing supply lines fit well in grroves cut in foam. An electric chainsaw w/o oil for the blade grooves well for romex cable. A hot knife works for everything else.