Anyone have any experience with mudjacking/slabjacking?

[Dangermouse]

Next in our occasional series of garage floor threads.

I have a garage floor that has sank at the front apron and am considering repair options.

One option is mudjacking or slabjacking, where a cementicious slurry is pumped under the floor and this raises the concrete. I have watched some videos and seen it done with driveway slabs, but I still have a hard time believing that it will lift a garage slab.


Has anyone used such a system, and if so, has it been a permanent solution?

[Cory W]

Disclaimer: I have never used this system, but am relaying advice from a person with 60 years experience in home construction, addition, and repair (practical-building and local Building Code research)

It is a viable solution, but as with most things, it all depends on who does the work. Any concrete mixture has its cure times for maximum strength, and you want them to follow those guidelines to the letter.

I would call companies who have such experience and see what they have to say. Is there anyone in your area who specializes in this, or is it an offshoot of general masonry work for most?

[DavidProehl]

I looked into having mudjacking done to a walkway in front of my house a few years ago. For a small walkway it was cheaper to tear it up and rebuild it, though I'm sure that isn't the case with a garage floor. Also, I was told they would need to drill several holes into the concrete to pump the mud in, which would leave repair scars after they filled them back in. Not an issue if you don't care about the appearance of the concrete or are planning to cover it, but something to consider.

Definately get an estimate, but from the research I did a few years ago it seemed like a good option. Just keep in mind that if it sunk once, it will sink again. It is only a matter of how fast.

[Dangermouse]

Yes, I'll certainly get an estimate on both replacing the whole floor and doing a mudjack repair, but of course the concrete guy will swear his is the only option, as will the mudjack guy.

David, if I did the mudjacking I would look at doing an epoxy coating afterwards to cover the holes and the cracks.

Of course the "best" repair is to rip the floor out and start over, but in my case it is complicated by the fact that the slab actually runs under the garage walls, rather than just floating between them. (Then I could build in a lift :) j/k).

That's kind of what I am interested in - has someone done a similar repair and then had problems 6/12/24 months later, or is it good for years.

[SS Spoiler]

I was a maintenance supervisor for a 400 unit apartment complex in Minnesota for 27 years. Being that I was there from construction on gave me good insight at what worked and what didn't. Due to hurried and sloppy concrete work I had a lot of first floor outside deck slabs sagging and cracking. An outfit called Concrete Raising came out and did a good job of lifting sunken and cracked decks with a slurry of crushed limestone [not cement] When some decks were replaced years later, the slurry was still soft and stable. All in all it was a good fix.


Paul Cerny #2691
Kalispell, MT

[Silverbullet]

Well, I had it done to a large outside patio. The Slabjacking I had done was NOT concrete, did not have to dry, they use a A B mix, the same stuff as we use for commercial spray in closed cell insulation. It expands and pushes the concrete up... the good thing is it pushes both ways so what ever was decomposing below or not compacted well, will be. I had it done a couple of years ago, and it is still great. The stuff they inject will not absorbe water or rot... it is pushed in at a very high pressure and then expands... they do several small 1/2" holes, when patched you don't really see them. Mine was $1500, a lot less than ripping out, hauling away, re-compacting, forming, paying for a pumper truck, and cement massons to finish... and done in 1/2 an hour with no mess...

They raise bridges and house foundations with the same stuff...

Craig

[Dangermouse]

I think I just assumed there was a little cement mixed in with the slurry mix to get it to set, but it sounds like the opposite is true - that it doesn't set.

All very positive feedback guys. Thanks.

[Spittybug]

I had 4 sections of my driveway ripped out, taken away and replaced with full rebar (none before), solid compacting and good concrete.... for about $4,300 for 530 sq.ft. Mine had a sink hole under it, probably a result of rotting roots. Without rebar it simply cracked and sank. This was less than a year ago, here in Houston.