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Discussion Starter · #1 ·
We have a basement floor in a new home that started to heave. The house is in a wet area but we took extra care becasue of it. Three drain tiles out side, one inside with 8-10" of rock under floor. All tiles drain to daylight. Were it has heaved is right were the trench for the geothermal lines that go outside are. It was fine for 5 months then they started up the geothermal heat and it cracked and heaved 2 weeks after that. The floor has been cut in 4'x4' squares becasue it is stained, but the crack still follows were the tubes were laid. It has heaved enough to crack dyrwall, make doors not work, and move floor upstairs. When I put 6' level across crack there is 1/2" under both ends away from crack. Any body have any ideas what would be causing the heaving ? I am going to be meeting with hvac and concrete contactor this week, just hoping to get some ideas.
Thanks
 

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Lift the house up and take a look under it... I will settle for 10% and if you find Jimmy Hoffa, then its all yours :laughing:
 

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if it is a new home built this winter sound like frost got under the house because of lack of snow cover unpacked soil because of the dig. how much fill is under the floor and what grade is the fill.
when did you start heating the house how often dose sump fill up
this year frost in mn is over 6 ft in a lot of places
 

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Are you on expansive clay? Clay soil will absolutely cause slab heave if it's not a freeze that's causing it. If it's clay you were suppose to saturate the soil before you poured. This allows the ground to be fully expanded before you poured your concrete. Slab heave caused by clay expansion can put as much as 15000 lbs of pressure per square foot on your slab. That's an enormous amount of pressure. I'm no engineer, but whenever I've built on clay it's always been a structural slab and engineered as such.

What does your soils report say? Did you even get a soils engineer to test it to see what it was?
 

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Are you on expansive clay? Clay soil will absolutely cause slab heave if it's not a freeze that's causing it. If it's clay you were suppose to saturate the soil before you poured. This allows the ground to be fully expanded before you poured your concrete. Slab heave caused by clay expansion can put as much as 15000 lbs of pressure per square foot on your slab. That's an enormous amount of pressure. I'm no engineer, but whenever I've built on clay it's always been a structural slab and engineered as such.

What does your soils report say? Did you even get a soils engineer to test it to see what it was?
I couldn't agree with you more, it definitely has something to do with hydro-static pressure.
 

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Discussion Starter · #10 ·
We started heating the house around late November with the lp furnace, they just hooked up the geothermal loops about a month ago. The crack goes diagonal across basement exactly were the geothermal pipe were put to the exterior loops. They did not fill their trench in with pea gravel like the plumbers did for theirs. No cracks where any plumbing trenches were dug, no other cracks in the 2500 sq ft floor any where else either.Basement was overdug for 8-10" of washed rock, poly, 2" foam, pex tubing, and then a 4" concrete floor. The water level in the sump pit is 10" below top of floor and has been that way since it was put in. It is in clay, we are used to that with over 50% of the homes that we do are. We have not had this issue before. The building inspector watched the drain tile and rock being put in and is the one who required extra drain tile.
 

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Discussion Starter · #11 ·
pappagor, this winter has been unreal hasnt it? We dug holes before the first of the year and their was alreay 3 ft of frost. We must be getting close to 50 days with sub zero temps this winter. Every town around me has all houses running water 24-7 to keep water lines from freezing. I have relatives that live only a couple blocks from mayo
 

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yes it has been $3500 over on heat for the homes that i have done or are doing right now
they are doing that here now to keep the mains open 61 day -0 or colder.
 

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This is where having your sub list you as an additional insured has real meaning. You did do that, right?
 

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Discussion Starter · #16 ·
Thanks, the pump is what I was thinking too. Today I looked at it some more, the floor heaved form the exterior all the way up to their pipes and then on the other side of the pipes where they quit digging it is perfect. I also had the thought of maybe one of their pipes have a leak. It is heaved the worst right in the middle of the whole basement. They should have filled their trench with rock but instead I think the filled it with the soil they took out.
 
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