By Kevin in West Chester, OH on 8/23/2005
I am using ICF on my house... when it came down to how many ICF
"Rows" there would be, given my desired 1st floor height, and my
self-imposed minimum required basement height (we have a walk-out)...
turned out that it made a lot of sense to 'add' height to the
basement. Meaning, that if I only had a 9' ceiling, the ICF
installer would have had to cut all of the forms 'to height' to achieve
this. This would mean cutting 11" off each form. Since I
had to purchase that form anyway, and the installer said it was less
labor intensive to just stack vs. cut the form, I had him leave the
entire row height un-cut. My basement, after pouring the concrete
floor, is 9'6".
Adding the extra height in my case was
minimal extra expense as it was primarily increased concrete (though
not a lot), offset by reduced labor cost by my contractor (he had given
me a 'before' price and then I did the height analysis and had him give
me an 'after' price), and also offset by some 'issues' I had with my
lot that required me to bring in back fill - at which point, having a
deeper basement, meant less backfill required.
Net - if you use
ICF, do a simple calculation to determine how many 'rows' you need from
footer to roof trusses and see how it comes out. You may find
there is some extra space just based on the heights of the forms.
Of course, you may find out the opposite too.
state permits you to use the ICF Block manufacturer's Engineering
data. I could have a 10' high basement, with up to 8' high of
backfill given the thickness of my ICF Walls (the higher the back-fill/
basement wall height... the more rebar is required).
understanding is with poured foundations, you can find different
foundation contractors with different forms. Many of the ones I
talked with (for my Garage wall) used an 8' form and then had to 'add'
an extra foot, which was more costly. A few of the foundation
contractors actually had 9' high forms... thus, more cost effective.
from a basement height perspective... I chose wood floor trusses, so
most of my mechanicals can run 'through' the trusses vs beneath
them. The cost of my trusses were very competitive with
TJIs. I didn't compare to dimensional lumber - but to get the spans
I wanted, dimensional lumber wasn't a great option.