Concrete floor heaving, help?

[moreyes]

I live in MN and have been in my house for 15 yrs, I have heavy clay soil, and of course frost. About a year after I moved in my floor heaved on the front half, under the both doors, and has settled, cracked and twisted, looks like the back half is fine, it stop cracking at the cut line half way back. So I am looking at replacing the front half, any recommendations on how to prevent this from happening again? The contractor who built my house did a poor job on the concrete. They did not seal the cut joints right away, so I know water from cars ran thru the cracks and that froze contributing to the heaving, I sealed them after the initial heaving, it help but now it is bad.

I have a floor drain in the big stall it drains to sanitary sewer, coded here allow it. I am thinking of having some of the clay removed and sand put in and compacted, putting a apron in front of the doors. How about insulation of some sort under the floor or inside the footings?

My Mens Crisis Center is 26 x 36 with 10 1/2' side walls, isulayed, sheet rocked and heated when needed.

 

[walrus]

2" of styrofoam anywhere you can get it will help. If there is clay under the concrete though you're kinda screwed if it freezes. laying styrofoam flat outside the slab, out 4 feet or so will help, making sure the edges of the slab are covered with styrofoam will help, heating the garage will help.

 

[IHI]

Two guaruntee's with concrete:
1. It will get hard
2. It will crack....no matter what precautions you take it will crack.

With yours, am i safe to assume the garage itself is on footings since you admitted to floor draines? If so, nothing to worry about with garage. If the outside approach slab is the one heaving, nature of the beast, moisture gets in the ground, ground freezes, ground moves. Ground starts to unthaw, moisture forces it's way back to the surface, ground moves.

so unless you have footings and proper insualtion in place, your not going to fix anything by placing foam alomng the sides of the driveway, the ground will still freeze under it and heave. Some soils lend themselves to more movement and it looks like since you have clay you got yourself a bad substrate.

 

[walrus]

so unless you have footings and proper insualtion in place, your not going to fix anything by placing foam alomng the sides of the driveway, the ground will still freeze under it and heave. Some soils lend themselves to more movement and it looks like since you have clay you got yourself a bad substrate.

Frost doesn't move sideways very much. In other words if you have foam down, the frost will form outside the foam but it won't travel far under the foam or at least thats what a study at UMaine found. So its possible one could help the situation by placing foam around the perimeter of the slab, down 6 inches or so. I doubt it would solve the situation though

 

[Gary S]

If you have to replace any of the concrete, also dig out some of the clay under it and replace it with nice sand. Sand makes the most stable base you can make under concrete.

 

[IHI]

Frost doesn't move sideways very much. In other words if you have foam down, the frost will form outside the foam but it won't travel far under the foam or at least thats what a study at UMaine found. So its possible one could help the situation by placing foam around the perimeter of the slab, down 6 inches or so. I doubt it would solve the situation though

What about all the grade under the concrete slab, that still contains moisture and still freezes so essentially still heaves, couple that with the fact it's clay which naturally holds water nothing to fix the heave other than to realize there's no way you can prevent it without footings and heat. Everything else is just a poke and hope band aid.

 

[walrus]

What about all the grade under the concrete slab, that still contains moisture and still freezes so essentially still heaves, couple that with the fact it's clay which naturally holds water nothing to fix the heave other than to realize there's no way you can prevent it without footings and heat. Everything else is just a poke and hope band aid.

Probably so.

 

[moreyes]

Got footings under the garage it is attached to my house, my thoughts are to remove some of the clay were the issue is and replace it with compacted sand. The drain does not drain under the floor, it runs to the sanitary sewer. I hate clay,

 

[jlbota]

Is there a footer under the garage doors or was it just a slab? There should be a footer below the frost line just under the garage doors to prevent just this thing from happening. If the grade runs toward the garage I would put in an apron with a drain that runs clear across the front of the garage to help keep the water away.
I would also remove some of the clay base and replace it.
Find a good concrete guy that knows what he is doing even if you have to pay a bit more. It will be worth it in the long run.

 

[moreyes]

Footings all the way around including under the doors, grade is drained away from the doors

So will foam help to eliminate my issue

 

[IHI]

So will foam help to eliminate my issue

No, foam will do absolutely nothing for you

 

[walrus]

Foam might help but if the frost penetrates the floor, its going to heave due to clay under it. I'd foam the perimeter, out 4 ft and I'd make sure the edges of the slab are insulated. If the garage isn't insulated very well, making it tighter and adding insulation might help. You're in a tough spot

 

[ColoradoBob]

In Colorado (and other places), we have a type of clay called bentonite which expands when it gets wet. No need for it to freeze, just get it wet and it swells. I don't know if this type of clay exists in Minnesota, but if that's what you're dealing with the fix may be different than assuming it's freezing. Best fix is to get rid of it and replace it with something more stable, like sand.