Sound concrete on top, empty space underneath
Westminster's wet-dry swings are hard on the soil even when the concrete above still looks perfect. The expansive clay pockets along the Big Dry Creek drainage shrink hard in dry years, and the open north-metro exposure, all that wind and sun cycling, dries the ground here faster than it dries the leafier suburbs. When clay pulls away from the underside of a slab, the slab doesn't sink right away. It bridges. It carries your car, the basketball games, the delivery pallets, over a pocket of nothing, until some load or some freeze finally asks more of it than plain concrete can give.
Void fill is the repair for that stage, before anything drops. We pump the pocket solid while the slab is still at grade, and the settlement never gets its chance.
How you find a void without a shovel
Tap the slab. A steel rod, a screwdriver handle, anything hard. Bedded concrete answers with a dull thud. Concrete over a void rings hollow, and once you've heard the difference you can't miss it. Trevor runs that tap test on every estimate, free, and it cuts both ways: sometimes a homeowner braced for a full lift learns a modest fill is the whole job, and sometimes a slab that "looks fine" turns out to be a bridge.
Where Westminster voids come from
- Shrinking clay. A couple of wind-dried summers can pull the soil clean away from a slab bottom, and the gap doesn't close back up when the wet years return.
- Fast spring melts. Snowpack that turns to water in a day or two moves quickly across open lots, and moving water carries base soil out from under slab edges.
- Downspouts and leaks. Concentrated roof water at a slab edge, or a slow plumbing leak below one, flushes out fines month after month.
- Young backfill. In the newer construction toward 144th, foundation and utility backfill keeps consolidating for years, and slabs poured over it end up spanning the low spots.
Fill now or lift later: the price difference
Void fill is quoted by volume, and most residential jobs land between $400 and $1,500. Half a day on site, back in service the same day. Compare that with what the same void costs after it wins: a settled driveway panel, a cracked garage floor, or a dropped basement slab, each one a bigger repair with a bigger invoice. The fill uses the same 1.5" holes and the same cement-sand-topsoil slurry as our leveling work, pumped at lower pressure so the slab stays exactly where it is while the pocket underneath packs solid. Once cured, the fill is harder than the clay that left, and it doesn't shrink on a dry year the way the clay did.
Our truck carries 10 yards of material, which matters on fills more than anywhere else, because a big pocket swallows slurry fast and a crew that runs short leaves it half-packed while they drive off for more. We don't run short, and the fill gets finished in one visit.
If the slab has already dropped a little and there's a void besides, we handle both in one visit, packing the pocket and pressure-lifting the slab back to grade. Howard tells you at the estimate which job you actually have. He's talked more than one customer down from a four-figure lift to a few hundred dollars of fill, and that habit is most of the reason our name gets passed around.
When to make the call
The day you learn the void exists. Every season it sits, the slab spans a load it was never designed to carry, and Westminster hands it a fresh freeze-thaw cycle or another fast melt to test it with. The usual triggers for a call are a hollow tap, a plumbing leak that was just repaired near a slab, an inspection report from a home sale, or excavation work next to existing concrete. The mechanics are explained in how voids form under concrete, and the service itself is on our void fill page.
The estimate is free and in person, tap test included, anywhere in Westminster. Call (303) 526-2222 and hear what your slab says before it settles the question itself.