Footing On Wet Clay

The General

We started on my personal home this last week and hit water at 2ft in 40% of a 600 ft waterline dig. We moved a lot of dirt for the pad and had soft spots at one end. Now the dozer guy says wait 2 weeks for everything to dry out. March is the rain season and I need to get the foundation done. Is there any way to dig the footings and drain them let the clay dry for a couple of days (3) then poor. Will the footing crack as the clay finishes drying due to proper irrigation later. Is there a method for installing foundations in the rainy part of the year. Ground is bedrock, red clay and some grey clay all mixed. The dozer guy also thinks there is shell deeper but 12 feet revealed nothing. I think that is it. Help need to keep moving this project along.

Teetorbilt

My personal opinion is that you are building on a tenuous lot. I would not place a typical footer type foundation here. The water, current problem, will be back.
My first thought would be pilings driven or jetted to bedrock.

PipeGuy

You REALLY should get a geotechnical consultant involved before you proceed further. Water at 2 feet deep can be indicative of a number of things and may or may not have much of an impact on your foundation design. As far as dewatering the pad area goes, you could install a sump pit at some location within the footprint, at least 4 feet deeper than your FF elevation, and run a sumbersible pump 24 x 7 to see if that impacts the water level / dries the soil. Homebuilders around here work year 'round and you can believe that if an excavator told them to wait for a pad to dry out they'd have another excavator very quickly.
As far as driving piles or drilling casings 70 some feet to bedrock...I don't see that being a cost effective alternative for your home. Three days of good weather, a good excavator and an experienced geo-tech should have you back on track.

hatchet

I'm with Teetor - when you start talking about clay there are all sorts of problems that need to be accounted for. With bedrock below clay the only direction it can expand is up. Drying out the soil for the pour is a temporary solution at best. I've seen clay expand 18" in 36 hours - imagine what would happen to your footing if that happens. The best way to counteract expansion is with caissons and void form. As pipeguy said - get a geotech to make recommendations on foundation design.

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Rich
WIT Construction Co.
Superior MT Contractor

PipeGuy

Google search for 'Geotechnical, Arkansas, engineer' should give you a place to start

The General

Thanks for all the feedback. I am going to take some pictures tomorrow. Right now it looks like piers on the east end of footprint with 2x2 footer on top of piers. Going to lay out the house and dig a little and see what we get. I think it is just too much rain. 5in in Jan. avg is 2.4 and Feb was just as bad. Pipe the actual footprint is dry but on one end (where the driveway would be)the dozer ran over the ground so much it started pumping water to the surface. Will post pics but it did rain sunday.

Teetorbilt

the dozer ran over the ground so much it started pumping water to the surface.

I'm really NOT liking the sound of this.

hatchet

I've seen ground where it's hard to walk on but when any heavy equipment rolls by it "pumps" making it look like a wave of water.. that's definately going to cause problems.

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Rich
WIT Construction Co.
Superior MT Contractor

The General

Well what's done is done. We poured the footing sat. Dirt was a 7 out of 10 according to the backhoe operator as for firm ness. We ended up moving the house to fit between the bad dirt and natural spring. Also took the whole elevation down to good dirt (4ft). 15k foundation just went to 30k but it is built the way I wanted. New foundation is now 5 block high with crusher dust fill (no basement). Also ground is now sloped around footing and cost myself a pumper truck with 100ft boom. The natural spring I refer to is going to be under my driveway to the side of my house. I had the backhoe operator cut into it and at 2 ft just in that area you hit solid bedrock. Looks like the water sinks into the dirt then runs along the bedrock down hill. I will still try to post pictures, for some reason the ioio port on a lap top is not the same as a home computer so I will have to post them from work. Thanks again all and I will keep everyone posted.

Teetorbilt

I'm staggered!
You never mentioned a natural spring!
I wish you luck on your new home.

PipeGuy

What part of that doubled the cost of your basement? The backhoe operator? The concrete pump? You said originally the block would be 3 - 4 courses tall, that's only 1 or 2 additional courses. If your foundation is 60 x 50 filled 5 block high that's less than 400 cy of fill.
7 out of 10 for firmness huh? If we were talkin' about woman I'd say you were in tall cotton. But since we're talkin' about foundations, I'm guessing you're in deep sh*t. Good luck.

hatchet

Whew.. clay with a natural spring nearby. I hate being negative - but I'll give it 2 years.

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Rich
WIT Construction Co.
Superior MT Contractor

jshuatree

I wander how this guys house turned out

Tscarborough

The foundation repair guys made a killing.

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brickstretcher

make sure u put 2 separate pumps in yr basement...yr gonna need it

CJKarl

Indoor pool

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greg24k

When building on clay soil,you have to make sure to give the load from the foundation and your house a wider area to spread over, so you will have to have a good drainage under your footings. Use a nice layer of 3/4 inch clean stone (8-10") under the footing.and the whole basement area in and out... use perforated pipe on the outside and inside of the footing tied in to the sump pump.Most likely your engineer will suggest that and to use a footing 2 maybe 3 times wider than your foundation wall with re-bar. Engineer will calculate everything based on what you have there,i.e. the weight of the house, strength of the soil,etc. Good idea to bring in fill for backfill to make sure you have a good drainage around your foundation. Don't use existing clay to backfill your foundation. Good luck

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Tscarborough

This was 5 years ago, FYI.

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stacker

i hear he has a nice trout pond in his crawl space.

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Rocha_Const

LOL, people dont look at the year this was written. I wonder also how did everything go...

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Rocha Construction, LLC

Flagstone Patios and Stone Work