I’ve read what I could find in the archives about ICFs, but didn’t find anything relevant to what I’m curious about. If the ICF pour is monolithic, it seems to me there would be basically zero water penetration through the wall itself. The water would end up at the footing, where it would come under the wall and fall into my interior drains under the slab. Correct or bad thinking? I’d be backfilling with clean gravel and filter fabric in any case, but I was thinking about forgoing the exterior drains since it adds a lot of disturbance to my existing house (I could daylight an exterior drain, but I’d have to excavate a fair distance of existing stuff).
MERC
Replies
You definitely need exterior perimeter drains to handle water. your first line of defense needs to be at the perimeter..
Like your first line of defense against the common cold is to wash hands and avoid sneezy people. What you are proposing is more like spending time in a tuberculous ward and depending on a garlic clove around your neck to ward off disease. Gartlic might help, but it should not be depended on as a primary defense.
Interior drains may help, but should not be the primary.
as for monolithic, That is true only in theory. Honeycombs are common even in normal wall pours where it is easier to vibrate. Voids are more commmon with ICFs
Excellence is its own reward!
The walls are pretty water tight but you will still need a waterproofing of some sort. It could be a peal and stick to a Drain mat system. I like the drain mat systems better then any othere waterproofing system. They provide a two layer protection for the the wall. If the top layer of plastic is damaged since there is an air space the water carries no pressure there for dropping to the footing drains.
Heres the waterproofing I use http://www.systemplaton.com/
There are a lot of different ways to waterproof an ICF basements.
Good luck
Brian
Thanks for the response. I had found that website yesterday and it looked like a good system. I also like the air gap drain systems because, like you point out, you get no hydrostatic pressure against the walls (until of course the drains clog up). I'm actually planning on putting patios and driveways (read: impervious surface) around the uphill parts of my house so the foundation is actually going to see very little water at all. I don't have any ground water around here, it's just surface water.
MERC