Leveling pool equipment concrete slab

[racharoow]

We've had our pool for about five years now. Each year I've watched our equipment slab slowly sink down on the left side. I've measured it to be about 3/4" - 1" out of level. I don't think much attention was put in to making sure the foundation of that area was well-compressed. It looks terrible, and I'm concerned there's some stress being put on the propane line and perhaps the PVC water lines.

Is there a way I can level the actual pad? It's about 3.5' x 6.5' and maybe 4-5" tall. Could I excavate around the left side and jack it up somehow? I'd just hate to snap the slab in two.

I've considered placing some Azek under the heater on the left side, this makes the pipes level, but I'm concerned that's only a band-aid fix.

Thanks in advance!

 

[JohnT]

I've done something similar, but there is a very good chance of breaking the slab. My situation was if we couldn't level it we were going to break it out and pour a new one, so we had nothing to lose by trying. It was the first section of sidewalk next to the stoop at a friend's grandmother's house that had sunk enough to be a tripping hazard.

I cut 2ft wedges out of 2X4s and drove them under the edge of the slab at several spots to lift it back to level. I actually wanted to raise the whole slab almost an inch and level it as well. I had to dig out enough around the slab to give me access for my wedges and sledge hammer. I think I used about 18 wedges for my 3X5 slab (and broke probably 10 more). Then I mixed very dry concrete and pushed it as far under the slab as I could get it with a couple of sections I ripped off the edge of a 2X4. After I had all the space filled, I let the concrete dry overnight and then pulled the wedges out. Worked perfectly...mostly. I broke off a couple of wedges trying to get them out. If doing it again, I'd have made my wedges out of treated lumber.

I thought about just using fill stone, but it would have dropped a little when I pulled the wedges.

 

[racharoow]

That's not a bad idea. I do have room to excavate and pound some wedges in there. And, I suppose if I did break the slab... I could pour a new one (after properly compacting the foundation!!!).

I like the idea of using PT. Could leave them in there with the new concrete.