What to do about a concrete slab with crack down center

[dchernikoff]

I have a 70-year-old wooden garage, on a concrete slab. Problem is the slab is cracked right down the center (front to back), and the sides have sunk a few inches -- to the point where they are below the surrounding yard level and when it rains a lot the perimeter of my garage gets an inch or two of water. The crack itself is about 3/4 of an inch wide.

What are my options? Jack up the structure, break up the slab and repour? Sounds pretty expensive! Can I just pour a few inches of concrete on top? But then won't it just keep cracking? Right now I've just put a carpet over it and I'm ignoring it, but the flooding once or twice a year is a big pain...

Thanks for any advice. Until I get this solved, I feel like any other garage improvements are moot.

-Dan

 

[Edger]

Most sunken slabs are caused by poor drainage that allows water to seep into the ground underneath. The ground becomes soft and wet, the slab sinks into it a bit, then the ground dries in summer, shrinks and the slab goes down with it.
I guess the floor should be stable if the original problem has been fixed.
The water can be caused by poor drainage around the area, a broken drain pipe underneath, no roof gutters, leaky water pipe etc.
If it is stable you need some concreting quotes to lay another on top and you will need a joint down the middle.
Send some pics so more members can comment.

 

[shambuda2000]

If the structure is reting on the concrete, i would call a foundation guy. Depending on the size of the structure you may only need a pier every 6 feet and they can dig under the slab and lift from the outside. Once it's leveled, you could simply chip away the edge of the crack and refill with fresh cement.

 

[admranger]

Pouring over the top won't work is my guess. shambuda2000's suggestion is where I'd start.

 

[buening]

You may also look into "mud jacking" as an alternative. It won't fix your crack but may help fix the settlement issue.