Is mud-injection a possibility?

[Rick Hurst]

Came across this the other day and am wondering what repair is possible. Has anyone ever seen possibly mud injection done to fill such voids. This patio appears to be part of the monolithic pour.

rick

[Jerry Peck]

Maybe.

There is also the risk of blowing that slab upward.

How far back does that go? You may risk damaging the foundation wall if (which is likely) the soil under the interior slab has also subsided.

I've seen successful pressure grouting (mud jacking in some areas), and I've seen slabs ruined by it, there is a risk. Okay, I shouldn't say "ruined by it" as they were "already ruined", so maybe I should say "failed to correct the problem and ended up making the problem worse".

[Matt Vozzella]

Even though it's a mono-slab I think there'd be big issues with just "filling the void" under the column. Additionally, with a monolithic slab the edges of the slab are thicker than the interior span, the void would have to be filled up.

[Jerry Peck]

Even though it's a mono-slab I think there'd be big issues with just "filling the void" under the column. Additionally, with a monolithic slab the edges of the slab are thicker than the interior span, the void would have to be filled up.

"the void would have to be filled up"

That what they do - fill the entire void.

[Brandon Whitmore]

Any chance of dry packing a bunch of mortar in there and letting the moisture from the ground solidify it? (that is, unless it goes way in)

[Jerry Peck]

Any chance of dry packing a bunch of mortar in there and letting the moisture from the ground solidify it? (that is, unless it goes way in)

"Any chance of ... "

Oh, yeah, a REAL GOOD CHANCE that will be attempted ... just will not do any good.

The way that would most likely be done would be to install a form board around the perimeter, core some holes down through the slab, inject some grout to create a layer a few inches thick, let that cure over a weekend, then inject more grout using the first grout as a solid bed for the new grout to put pressure against, pumping in the new grout under pressure so as to create upward supporting pressure for the structure.

Too much pressure and too much grout and that slab will belly up and a little more will crack it, and a little more will break it into piece, one has to know what they are doing, and, yes, there is always the risk of "over doing it" even when one knows what they are doing.

[Jim Luttrall]

Yep, it can be done... but I am wondering where the grade beam is that should be supporting the column(s).
I would be punting to an engineer on this one.

[Jerry Peck]

Yep, it can be done... but I am wondering where the grade beam is that should be supporting the column(s).
I would be punting to an engineer on this one.

Pressure grouting should only be done by an engineer anyway. It does become an "engineered" foundation.

[Jim Luttrall]

Pressure grouting should only be done by an engineer anyway. It does become an "engineered" foundation.

In the perfect world, yes. But here in Texas, the only things needed to be a foundation repair company are a pick-up, shovel, and a jack and you can borrow those!
There are some, but not all, municipalities that require engineering.

[Ted Menelly]

Even if it was part of the interior slab pour there is a grade beam around the interior slab. I doubt there wiil be any affect on the interior slab pumping concrete under the patio unless they just go wild and force inject the mudd and pay no attention to just filling the void. I would also suggest digging down around the perimeter of the patio and adding at least a bit of footing.

[Ted Menelly]

Pressure grouting should only be done by an engineer anyway. It does become an "engineered" foundation.

And you mister Jerry are seriously in love with the word engineer. This is way to simple a fix to get an engineer involved. I almost hired an engineer to design the load of each spoon full of breakfast I had this morning so I would not hurt myself carrying to much to my mouth.

[Rick Hurst]

Jerry,

I slid an 8ft. piece of pvc under that patio towards the rear wall before I hit anything. Did defer to a SE, but I'm wondering what would have caused that soil to settle as such. It almost appeared as if it had washed out.

rick

[Ted Menelly]

Most of it was more than likely a compaction problem. There was a hollow spot there and they filled it but did not compact properly the rest was wash out from the slope to the side and rear of the property. What you hit was the grade beam around the perimeter of the foundation. Another huge mistake was not adding a footing around the perimeter of the patio as they should have or at the least under those columns. the soil not touching the bottom of the patio was not a big concern but with no footing at the very least at the columns is. It is going to just crack at an angle across that patio and the columns are going south along with the roof over it.

[Scott Patterson]

I have never really seen any good results from mud jacking. I have seen many bad outcomes though.

I did see a home the other day that was jacked and the foundation stabilized with a foam product that was injected under the slab. This was a first for me and I have been told that it is better than mud jacking. I don't know anything about it.

[brian schmitt]

pressure grouting was recommended and used quite often after the northridge,calif earthquake in 1994.i inspected hundreds of houses that i recommended an engineered fix for the voids that were a result of liquifaction. it should work here.

[A.D. Miller]

Came across this the other day and am wondering what repair is possible. Has anyone ever seen possibly mud injection done to fill such voids. This patio appears to be part of the monolithic pour.

rick

RH: If, as you appear to believe, this is a monolithic pour, where is the perimeter footing? It is hard to tell from your photo, but some of the edge does not appear to be 4" in thickness.

Mud-jacking may indeed fill the void, but it will not replace the required footing and will not address the cause of the loss of soil, vapor barrier, etc. And, like SP said, mud-jacking is often more damaging to the foundation than the condition it is used to repair. This is especially true when performed by the typical fly-by-night grubbers that inhabit that particular profession.

TM may not like deferring to engineers, but this, in my opinion, is one of the many times it would certainly be appropriate to do so.

[Richard Stanley]

"I did see a home the other day that was jacked and the foundation stabilized with a foam product that was injected under the slab. This was a first for me and I have been told that it is better than mud jacking. I don't know anything about it." - Scott P

Coincidence - yesterday a client asked me about foam use to stabilze foundations - said he saw it on a tv home repair show. I know nothing about it - does anyone????

[A.D. Miller]

"I did see a home the other day that was jacked and the foundation stabilized with a foam product that was injected under the slab. This was a first for me and I have been told that it is better than mud jacking. I don't know anything about it." - Scott P

Coincidence - yesterday a client asked me about foam use to stabilze foundations - said he saw it on a tv home repair show. I know nothing about it - does anyone????

RS: Polyurethane like the highway departments use to fill soil voids. Pricey for residential applications.