I'm starting planning for a small ICF house, 2000sf or less.

I'd like to get an idea of how much I'm going to need to budget for concrete. To get pricing on concrete I need some info about what mix I should use.

I live in Vermont. A big reason for building with ICFs is so I can get longevity and avoid moisture hassles.So I'm willing to spend a bit extra for a mix that will be waterproof, if that's possible and worth the extra cost. I realize that any voids would allow water in, but I'd like to avoid having the concrete wicking moisture up into the structure.

I like the idea of building into a hillside, but I also like the idea of building on a slab on grade so I just don't have to deal with water issues.

If there's some sites that folks can recommend that I read first, please let me know. I've been doing some general research for a year or two now, but I'm just starting to really get into the details.

Thanks for any info!

Vermonter,

Will you be building in an area where the earth is exceptionally wet?  If so, you could wrap the footer, wall and slab with a waterproofing membrane that should stop the capillary action of water.  You could also use fly ask and other additives to tighten up the concrete.  Proper vibration of the concrete (not the forms) should eliminate the voids.  By the way, higher strength concrete is more water resistant.

If you build above ground, it is fairly easy to protect the slab and concrete walls from moisture.  An elevated slab (raised slab) should be considered instead of a slab on grade.

Maybe some other forum members will comment on my thoughts or add more info.

I don't have property yet, so I don't know the site conditions. I'm trying to get an idea of building costs so I can figure out how much property I can afford. I'll be doing a lot of the work myself.

standard (16"x48") forms are .111yds or one yd of concrete per 9 blocks. Approximately 7 1/2 90 degree corners per yard of concrete. I've used eco-block and reward here in South Carolina and they both have good estimaters on their websites

You might consider an admix such as Hycrete that makes the concrete hydrophobic, but any discontinuities, cracks, honeycomb, etc. will be weak spots.  With ICF, you will never know the weak spots are there, however. <http://www.hycrete.com/>  It is also a green product with Cradle to Cradle credentials.  There are other hydrophobic admixtures and surface treatments, too. 

If you are after a WATERPROOF STRUCTURE, then you should think about conventional cast in situ walls with waterstop between the wall and footing and possibly the slab, using a hydrophobic admix.  The devil is in the details...no cold joints, etc.  This approach requires near perfect QC and technique.  Accordingly, being able to visbly inspect the walls is important. 

Just because you have a slab on grade does not mean you are immune from water problems.  Good surface grading and proper footing drainage are your best defense.

Bruce

Hugh, where are you in SC. If you are new; welcome. I'm in Fort Mill.

Vermonter.
When you know how thick your concrete core will be and how much rebar will be in your walls, plus the other extras you are considering putting in you will have a much better idea of how much the concrete will be. If you have not contacted your local ready mix company yet, find out how much it will be for a 3,500 to 4,000psi pea gravel mix with around a 6" slump- per yard. Make sure they include taxes and all other fees they would charge in their quote. That would be a good place to start. I have never built in Vermont, but don't imagine it would be more than $125 per yard, but thats only my assumption, and again, you will have a much better idea when you know which mixtures you will be adding.

Thanks Aaron, that's the info I was looking for. Is that a fairly standard mix for ICFs?

I worked on a renovation this spring where we poured a footer and 4ft foundation wall built of ICFs for a kitchen addition. I don't know what the mix was, probably nothing special, but it was $99 per yard.

Hi Aaron, Sumter SC is now home. Was Beaufort/Bluffton/Hilton Head. I sent you a message with other info

hi, let me know what your rough cost is... I am considering a similar situation.

3-4 bedrooms, 2 1/2 baths, plus unattached garage. for about 2500 living.

so far from the great people here, going to be icf walls and roof/attic will be icyene. (sp?).

I need to understand the cost, i am a newbie. I only helped my grandpa to build houses when i was younger, i never went into the cost of materials.

thanks.