We are in the middle of building an addition to our existing house.  We used ICF to form the basement walls.  We have a walkout basement with 10' walls.  The construction has a tile drain which slopes to daylight on the exterior and an interrior lone which drains to a sump pit.  The construction was mated up to our existing structure so we only have two walls that are new.  The builder applied the stick and peel membrane along with the dimple membrane to the exterior walls before backfilling.

Here's the problem.  We have had water problems since day one.  The latest issue is when it rains, water appears along the ICF and the floor.  By water I mean standing water which pools across the floor until it runs into the sump pit.  Upon closer examination, I noticed the water was coming through the foam not up from the seam between the slab and the foam.  The interior tile line is dry most of the time and we only see the water problems when we get a good rain storm.  The exterior of the structure is complete with roof, gutters and sloped backfill.

I cut away a section of the foam about three inches up from the floor and down to the footer and found that the wall is quite wet and water was seeping through the concrete and was now able to drain under the slap and hopefully to the interior drain tile.  We know the exterior drain tile is working since we can see water running out during a heavy rain.  The builder cut the remaining foam away from the wall down to the footer on the entire perimeter and we could see multiple wet spots in the wall.  The wet spots usually had a high concentration of aggregate and looked more porus that the rest of the wall.  The builder patched those areas with hydraulic cement and we are in a wait and see mode.  The plan moving forward is to seal between the slab and the foam walls with plastic sheeting to form a moisture barrier before we start to finish the basement.

Any thoughts about this as a solution?  Should we be getting that much moisture in the concrete itself and will that be a problem in the long run?  I am concerned that we are putting a bandaid on a problem that will haunt us for years to come.  On the other hand, I have to pay for repair attempts and am unwilling to excavate the entire exterior to find that we did exactly what the instructions said and we start to blindly try things to stop the unstoppable.  (We've been doing that for quite a while)

Thanks,
Grant

This situation sound eerily similar to Cityslickers problems.

Your weeper tile is your first line of defense.

If your perimeter tile is at the proper elevation, (invert at underside of footing )

you should not experience any hydrostatic pressure, or water infiltration above the tile level.

A sloppy installation may have it back sloped or draining towards your interior.

I am not a fan of peel and stick membranes for ICF's as water will become trapped behind it ,
 
with no way to exit, and will follow the path of least resistance.

"Air gap" membranes however, provide a direct path for water to travel to the perimeter drain....... always.

I know some installers feel the need to "double up" their systems , but the reality is something different.

It seems when peel and stick used and there is a problem, the water tends to come from above.

Short story, couple years ago a contractor called us frustrated that a new church ICF addition was leaking. It was a walkout lot, the below grade portion had water in the basement. The ICF installler in the area dug up the foundation and rewaterproofed the foundation THREE times at his expense.
Turns out the roofer butted his step flashing to the old structures building paper, water from the roof of the original structure was getting into the new roof system, following a truss to a gusset above the wall, trickling onto the wall where the concrete was a little lower than the foam and dropping 25 ft. along the inside of the foam before exiting on the interior of the basement. They used peel and stick, which as Eric says, does detriment when the water is inside the structure. Oh, the whole church and therefore coffee shop and town decided that "them foam blocks leak" and the ICF installer was never reimbursed for his extra work!
Moral of the story, sometimes when you have water below, look up, specifically at the framing/ICF juncture, and window/door flashing and patio junctures also.

Heres an idea to see if your water is coming in below. Go to your local hardware store-not Home Depot, ever- and get an adapter for garden hose to PVC, and 8 ft. of 1 inch or so pipe. Jet the pipe down vertically till you fell the gravel below, and turn down the hose so water isn't bubbling above ground. If your tile works, your floor inside will not be wet even after a couple days, and your sump/daylight drain should show some flow. Before jetting the pipe down, measure how many turns on the hose bib equals how many gallons per minute to get an idea what kind of water you will be pumping underground.

Kevin

Sorry if this is posted in the wrong place, but here goes. I want to build an ICF house in NC on a 4 acre plot next to a river (somewhat swampy area). The river could flood over during a hurricane hence the land is considered in a flood area. Either way, others are building stickbuilt homes with 5 ft crawl spaces and decks to ensure the house is abover the potential floodline. I had an idea to just poor a slab, build up the wall to 7-8 ft, super waterseal it, then using soil that Iwill dig out from an acre size pond on the land, backfill the walls to top of the "basement" with a 30 degree slope or maybe less to create a hill around my house. Then I'll build a 2 story ICF house starting at the top of the basement wall. The effect will be to have a house on a small hill with a basement, though of course in reality I built it ground level. However, it absolutely, positively, without any room for doubt, must be waterproof--forever. I figure if people can build concrete swimming pools to keep water in, then I can build one (the basement) to keep water out. Anybody, know of any similar projects. I thought of lining it with a pond liner after spraying it with globs of sealant and etc etc.(Think earth home in a swamp, except just the basement. ;-). What is the best way to waterproof that?
Jonathan

Chicano,

Where I live we build houseboats that float on a concrete basement.  Essentially we build concrete boats under the home, as a matter of fact we have several floating bridges in the state that are all built on concrete floats.  So with that being said, yes your idea of building your concrete houseboat on dry land can be done but one of the issues you will need to deal with is bouyancy.  If a 5 to 10 foot storm surge comes and you properly build your basement like you say then your home could lift out of the ground and float away.  I have seen similar things happen to homes in floods that the pressures started to lift the house then usually the floor gives way and the basement floods.  But with proper attention to detail and possibly running it past a marine engineer you could do what you say.

ICF Contractor

ICF Contractor,
So let me get this straight. I have two options:
A: build it Not water-tight so if the area floods my home will flood, but NOT float away because the water can just rush in
or
B: build it water-tight but risk it floating away.
Wow, I never thought of that before. Seriously though, I will definately add that to my list of questions for the engineer. I am not sure it is such a problem since I plan to "backfill" or rather push soil up around the basement probably 6 or 7 feet high and taper it out to create a hill. I think I should be able to keep the water well away from the house.
Ok, to not completely hijack grantb 1780's topic, wouldn't he have the same problem if he waterproofs his basement? When the water table rises could it float? Sorry if this is a dumb question.

Hi chicano:

You are right ... we don't want to sway too far from the original post.

Now, refering to your first plan, what you would be doing is building a mat slab ... technically speaking a raft on which your house will be built.

Now to ensure that it would not float ...

1. considering the maximum flood level (let us say on a 100 year return period) and the bottom of your raft slab, one would be able to compute the maximum hydraulic head, and from the surface area of the raft, you would compute your maximum upward force that would tend to lift up the house on the raft and make it float
2. you would then make sure that the weight of your house, the weight of the raft slab and and any backfill resting on part of the raft would be larger than the upward force in 1. above

I did have a case where the upward force from the hydraulic head was larger than the weight of the house and the basement slab all taken together -- so I had to use screw tie-anchors in the basement slab to gain additional resistance against the upward force on the house.

So, what I am getting at is that YES your engineer should be able to compute the uplift force and the counteracting force and then make sure that even under the worst of conditions the house would not float.

Of course there are other things to consider, higher insurance rates for building in a flood plain, need to have back-up power, use of back-flow prevention and so on ...

but there you have it.