My house plans call for French doors that open to patios as well as the lawn in several places, and for the doors to be just slightly above exterior grade. The plans also have a basement. With traditional construction the first floor deck would rest on top of the basement's poured concrete walls (see attachment), this would make it very difficult to have the French doors open to the exterior grade (really, more like ~4" above grade), because the grade would be too close to the floor joists, and would rot the wood. Also, IBC calls for wood joists to be at least 6" above grade (unless treated, etc., etc.). If we use ICF, I understand (I think I understand) the floors would 'hang' on the ICF walls. This makes me wonder if our original plan might work after all, if we use ICF. Does this seem right? Also, if the floor is still technically 'below' grade, even partially, would the first floor be considered a first floor, or basement? I don't want to get into trouble with valuations, etc! Note: See attachments for rough examples of what I'm describing.

There is no rule that says your floor joists HAVE to set on top of the basement wall. The joists can be hung to the inside of whatever type basement wall you choose to use. The exact detailing would vary by the type of systems you choose. Your designer or builder should be able to help with that.
Another consideration, what type above grade exterior wall are you planning to use? 4" clearance is not really acceptable for any type wood construction, unless you use pressure treated throughout.

Wes, I was imagining using ICF for the above grade (framing), in fact for the entire exterior to the roof. Final exterior will be stucco, but any final exterior will be at the prescribed separation from soil, etc.

Really, I'm just trying to avoid using pressure treated wood for the first floor deck, since, regardless, I don't like the idea of wood being too close to the grade. ICF seems ideal for this, since in multiple story installations, the floor appears to need to be 'hung' on the inside in some way, thus moving the wood away from grade.

I have recently found that a traditional poured foundation could work too, by creating a 'brick ledge', but on the interior of the wall, which the first floor deck would then sit on (a bit simplified). I think this approach too could be accomplished using ICF? Though, I originally envisioned something like this diagram: http://www.toolbase.org/CAD/CadPNG/ICF-BsmntSprtICFCnst.png.

I guess I'm just wondering if the first floor is partially below grade, would that pose any other unforeseen challenges (code, etc). The reason for this design is to expand the inside spaces by making the outside more accessible/at close to the same level.

Posted By eerkel on 23 Oct 2010 08:47 AM
Wes, I was imagining using ICF for the above grade (framing), in fact for the entire exterior to the roof. Final exterior will be stucco, but any final exterior will be at the prescribed separation from soil, etc.

Really, I'm just trying to avoid using pressure treated wood for the first floor deck, since, regardless, I don't like the idea of wood being too close to the grade. ICF seems ideal for this, since in multiple story installations, the floor appears to need to be 'hung' on the inside in some way, thus moving the wood away from grade.

...

I guess I'm just wondering if the first floor is partially below grade, would that pose any other unforeseen challenges (code, etc). The reason for this design is to expand the inside spaces by making the outside more accessible/at close to the same level.

I did pretty much this same thing except with a crawl space instead of a basement. I posted pics about 2 yrs ago. If you can't find them by searching on my user ID, and want to see them, let me know and I'll upload them again. The pics show the concrete sills I put in, and how I did a thermal break from inside to outside.

sorry to get of topic but im looking for extentions for owr wall braces were using superior allinment system call glenn at 605 520 0314
thanks glenn

Eerkel

If you use all ICF exterior walls, you can bring the grade up higher than you could typically with more traditional frame platform construction. There are couple typical ways to support a floor platform when you have an ICF foundation and above grade walls.

The most common is probably to utilize the same thickness foundation and above grade walls and utilize something such as the Simpson ICFVL hangers to support a ledger for the floor platform.

An alternative is to use a thicker foundation wall and thinner above grade wall and utilize the offset to support the floor platform (see the attached drawing). This method is fine but probably more complicated than the first.