I was hoping to have an ICF basement with SIPs walls.
    Last week I brought in an excavator to dig a couple of test holes.  I had figured that the footings would be 8' below ground level.  So 2 test holes were dug.  5' of dirt, then all clay.  There was lots of water running on top of the clay.   The ground water settled in at 5' below ground.
    What do you think?  Is there any possible way to end up with a basement?   The lot is fairly level, so I don't really have a logical spot to divert the water to.   I really did want a basement, but as it looks now, I'll just have to increase the footprint of the house to get the space.  Any ideas??
Thanks  

Meh. Not knowing your surroundings it's a bit difficult to say.

You could put in your basement with perforated drains feeding a sump pump, but a couple things to be aware of:

- If the power fails you'll have a flooded basement. This can be ameliorated if you dig a drainfield for the overflow. But this depends on what's around you; whether you can get out of/ above the clay with a line.

- If there's alot of water on that clay, it'll be hard to fight. How deep does your borehole fill over the clay? (water table) If alot, best would be to make a distraction for it. Find where it mostly comes from and dig swale trenches with plastic liner on your side to route it around you.

About all I can say with what we have.

Are you saying the ground water table is 5 feet below ground. My personal choice wound be to not try to put a basement below the water table. Eventually the water will win.

Can you redesign your house and landscaping to put your basement in just above the water table? Some variation on a split foyer? Or raise the front yard grade around 3 feet with fill dirt?

BTW sometimes ground water table height varies from year to year and season to season. I would want to set my basement height based upon the highest expected ground water table rather than the current table.

We have installed many successful basements in similar conditions.

Firstly, your footing should bear on the top of the clay, as long as soils tech approves the bearing capacity.
Notice that the water travels "on top" of the clay layer.
Excavating into the clay will create a "bowl" effect that will always draw water to it, and have you pumping to infinity.
From what you describe, you may have 3 ft of foundation wall showing, when done. Better that, than 6 in of water in your basement. LOL
Pour a 10 in thick footing and install a perimeter weeper tile system with clear stone coverage and interior sump box.
Place clear stone also,level with the top of your footings to create a water retention area under your basement floor. Make sure a drain tile is installed into this layer, and connected to the sump box.
We use a Stone Slinger to accomplish this. 80 tons of stone or better is not uncommon for an 1800 sq ft home. A Telebelt works fine too.
This clear stone will allow for many thousand's of gallons of water to be collected and pumped in season.
Use filter cloth on your tile, geo fabric over also on exterior tile . Air gap your buried ICF foundation exterior.
Vapor barrier underside of your basement floor, and better yet, install rigid foamboard underfloor also,to reduce heat loss thru the basement floor.
Payback is immediate.


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