Support beneath the slab

Concrete Void Filling in New Mexico

When water or settling washes out the soil under a slab, we fill the empty space with polyurethane foam so the concrete is supported again. Sometimes that is all it needs; sometimes it needs lifting too. We’ll tell you which.

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What a void under concrete is

A void is empty space between the slab and the ground that is supposed to hold it up. Water washes soil out, fill settles, or something buried breaks down, and the slab ends up bridging a hollow. You usually cannot see it from above, and the slab can crack under a load it used to carry fine.

Signs worth a look

A gap you can see under an exposed slab edge
The slab rocks or moves when you walk or drive on it
A hollow sound when you tap one area and compare it to another
Settlement next to a joint, a trench, or a drainage path
Soil washing out from under the slab after rain or irrigation

Three different jobs

A slab problem can need one, two, or all three. The estimate says which.

Void filling

We inject foam into the hollow so the slab is supported again. The slab stays where it is.

Concrete lifting

The foam expands and raises a slab that has dropped, filling the space underneath as it goes.

Fixing the cause

Stopping the leak, moving the downspout, or regrading so the water stops taking the soil. Sometimes that is a plumber or a landscaper, not us, and we will say so.

How the job goes

We look at where the slab moves, where the water goes, and what the edges show.
We mark the area to treat and decide with you whether the slab also needs lifting.
We locate joints, drains, and known utilities before anything is drilled.
Small holes, foam injected a little at a time while we watch the slab.
Holes patched, and we tell you when the area can take traffic again.

Has the slab dropped too?

See how we raise a settled slab back into place, from inspection to patching.

See how concrete lifting works

Concrete Void-Filling FAQs

Gaps you can see at an exposed edge, a hollow sound when you tap the slab, rocking underfoot, or washout next to a joint or downspout are the usual signs. We check for those on the site visit and tell you what we can and cannot see from the surface.

Not quite. Void filling puts support back under a slab that is still sitting at the right height. Lifting uses the foam’s expansion to raise a slab that has dropped. Many jobs need both, and the estimate says which.

It restores the support that was lost. Whether the slab stays put depends on the soil, the water, and whether the cause (a leak, bad drainage, erosion) gets fixed. We point out the cause when we see it.

No. Foam fills the space the water left behind; it does not stop the water. A leaking line, a downspout dumping next to the slab, or grading that sends water under it needs its own fix, sometimes by another trade.

Concerned about support beneath a slab?

Tell us where the gap, washout, or hollow sound is. We’ll inspect it and give you a free estimate.

Schedule a Visit Send Plans Call (855) 575-3626