Mudjacking to fill void?

[tightwad_wrencher]

Previous owner of our property never installed gutters on the garage and now I'm left with a void to fill. The slab has hair line cracks, nothing too major yet. I have bounced a lacrosse ball on the slab and do notice a tone difference where the void is. My plan as of now is to get gutters and drain tile installed reaching out to the lower end of the property. Then having the void mudjacked until I have the funds to totally rebuild the slab and add on. Opinions?

 

[36truck]

Mud jacking works great. I've had it done to raise a slab on one side to get it level. I know they mud jack in big Industrial building to raise a floor.

 

[Daniel Dudley]

If you have a void on the side of your slab, you need to dig it out, form it up and pour it. If a mud jacker comes, they will form it tight to the slab, and pump it in, I guess.

 

[Dominico]

Had two experiences with mudjacking and both were good. Make sure they gradually and slowly raise the slab in several different areas via the predrilled holes. If they attempt to raise the slab all at once you may get additional cracking. They should pump the material in a little each time continuing around the area until level. Mine has not moved in over 8 years! That's pretty good considering the climate swings in Michigan. In my opinion if the concrete is in good condition and a total tear out is not necessary this is an inexpensive alternative.

 

[NUTTSGT]

I'm guessing you have a pole building or something similar with just a slab floor and no footer ?


If you have a footer and have a void under the concrete floor, I'd guess it due to improper compaction before pouring the floor. Otherwise, it's washed out a lot more than you think undermining the footer too.

 

[volleyball]

If it is only temporary, how about drilling two holes and pumping in filler yourself? If void is large, maybe start with gravel.

 

[Art From De Leon]

I leveled a 100 ft (+/-) grain leg once. The owner had pre-installed 10 or 12 2" *******, each with a ball valve to trap the pressure, thru the slab, and had set up two transits to verify the amount of movement back to vertical, that we were achieving by pumping 'grout' (cement) under the slab. We just used the booster pump (30-35 psi) and pumped thru a rag hose to achieve the goal. Good radio communication between the pump operator and the men on the transits was required to keep things under control.

 

[tightwad_wrencher]

I'm guessing you have a pole building or something similar with just a slab floor and no footer ?


If you have a footer and have a void under the concrete floor, I'd guess it due to improper compaction before pouring the floor. Otherwise, it's washed out a lot more than you think undermining the footer too.

Its a garage built on a slab that's only 2.5"-3" thick no foundation other than a base layer of gravel.

 

[tightwad_wrencher]

If you have a void on the side of your slab, you need to dig it out, form it up and pour it. If a mud jacker comes, they will form it tight to the slab, and pump it in, I guess.

There's a good hollow thud when bouncing a lacrosse ball on a 3'x3' corner by the man door.

 

[Lassen Forge]

It'll not only vill the void but help stabilize the soil under the void as well. Well worth it, tho be ready for it to take more "mud" than expected - sometimes those voids are pretty big.

If the ground is soggy/boggy, you *may* have to go in more than once - once to seal the bottom of the void, once to fill, and once to level. *****, but thats the nature of the beast.

Slow - *VERY* Slow - is important, especially when you hit the top of the void, to avoid either busting the slab (or seting up a future slab-busting pyramid underneath) or taking the slab out of level. Make sure whatever they use - laser levels, stringlines and torpedos, transits, etc. - that they know what they're doing, and more importantly KNOW WHEN TO STOP!

Another caution - if you have any underground utilities going into the slab (esp. electric conduit, for some reason) make SURE you can keep an eye on the bozes, etc... I can't tell you (a) how many times we've filled electrical boxes, making a mess to deal with, and (b) how far up and down a piece of conduit or unknown void that stuff will flow.

Any questions, PM me.

(ref - I worked on a highway mudjacking crew as a Drill, Acker & Stinger operator for 5 years, learned from a guy who did it 30+ years... fun stuff!)

 

[ford33]

I had 20 feet of sidewalk mud jacked. After mud jacking it looked fine. But in less than 7 years the sidewalk had sunk again. I then had the whole sidewalk replaced.

 

[tightwad_wrencher]

I had 20 feet of sidewalk mud jacked. After mud jacking it looked fine. But in less than 7 years the sidewalk had sunk again. I then had the whole sidewalk replaced.

That's fine with me. I just need something that'll stabilize the slab until I can get 30-40k saved to rebuild from ground zero.