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Leveling a tilting concrete slab

1K views 12 replies 6 participants last post by  Magnum 
#1 · (Edited by Moderator)
I hope I am putting this in the correct forum.

I just wanted to see if anyone else on here has had experience with leveling a tilting concrete slab? I have a 10' x 10' slab at the bottom of the deck stairs. I dug under it in a couple places and put jacks under it. I raised it up so that it was level if not a tiny bit more than it needs to be. My thinking is to add some slurry under it and then when I finally set it back down that it should be slightly tilted away from the house so water will run off away from the house. I have it cribbed up with blocks at this time. I have drilled four pilot holes thru it in locations that I think will be best for adding slurry. I will rent a core drill next week and punch thru some 2" holes where I have already drilled pilot holes. That's where I am at now with with project but I wanted to see if the way I am going about it sounds right to you all. I am planning to feed the slurry of sand and gravel and cement down thru the holes and pack it in there with a ram. I am also planning to shovel some under the edge where I have excavated and then using some sort of ram, pack it under from that position. I'm sure hoping this will work because in order to get a pumping rig in here to do it, it will cost 1-1/2 times what I paid for my table saw. : ( I just can't afford to spend $1000 to level a slab. If I have to, I will use some foam under it. Not that I want to.
 
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#2 · (Edited by Moderator)
I sure hope your idea works for you as it did for me, I did almost the same with one approx. that size in the front part of my dog pen. That was two years ago after raising it one inch above level. It has ( so far ), worked real good and has only sunk down around maybe 1/4 inch or so. My subsoil is heavy in that area and may have a different effect on yours.
 
#3 ·
Thanks for the response Mel. That gives me hope. It was blowing a hooley all night last night and is now snowing hard so I will probably wait until next week to get back on it.
 
#4 ·
I guess my question on this project would be: How much would it cost you to put in a whole new slab with a better base to prevent future subsidence. Or to replace it with some other materials like brick, flag stone, etc. The latter items could also be "re-leveled" if the sinking happens again.
 
#6 ·
LesB, I haven't priced a new slab but can imagine it being upwards of 3G. I have no idea about brick. Just to get rid of a 10×10 slab would cost me more than I want to spend.

Fresch, maybe foam would work and would save me from renting a core drill. Have you had any experience using it and do you think it will hold up. I may need to rethink the idea of using foam.

Mike
 
#7 ·
Well tomorrow about this same time, we will have a better idea if the foam works. I sprayed five 16 oz cans down thru the little 3/8" holes that I drilled in the slab. I'll try to look back under the slab tomorrow to see what it looks like. Regardless, I will pack some fines in from the edges of the slab and then let it down off the cribbing. Got my fingers crossed. If successful, it only cost me about $20 plus drilling the holes and digging made me so sore I could barely walk for a couple days. I gotta get in shape!
 
#11 ·
I had already raised it to level so I didn't need the expanding stuff. I just shot the foam in thru some holes that I drilled. Hoping it will set up enough to hold the pad. It was just some Great Stuff foam.
 
#12 · (Edited by Moderator)
I sure hope your idea works for you as it did for me, I did almost the same with one approx. that size in the front part of my dog pen. That was two years ago after raising it one inch above level. It has ( so far ), worked real good and has only sunk down around maybe 1/4 inch or so. My subsoil is heavy in that area and may have a different effect on yours.

- mel52
Totally agree with Mel! I did the same sort of thing for a friend last year on 1 of 4 Driveway slabs. Worked Just Dandy!
 
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