Lakewood is prime void-fill territory, and it comes down to grading. When a city is built on lots cut into a slope, water spends every melt season moving downhill through the soil, and moving water carries soil with it. The slab on top doesn't sink right away. First, a cavity forms underneath while the concrete bridges over it like a tabletop missing a leg. That cavity is a void, and filling it while the slab is still at grade is the cheapest concrete repair you'll ever buy.
The sound of trouble
You can find a void yourself in thirty seconds. Take a screwdriver handle or a steel rod and tap your way across the driveway, patio, or garage apron. Supported concrete answers with a dead thud. Concrete over a void rings hollow, a drummy sound that changes pitch as you cross the empty spot. On graded lots we find them most often at the downhill edge of a slab, under aprons, and anywhere a downspout has been discharging for years. During every estimate we tap-test the whole property free, because finding a void early is the whole game.
Where Lakewood's soil goes when it leaves
The clays along the hogback don't dissolve, but the slope wash mixed through them moves easily once water gets flowing. Foothill-edge storms load the west side with more snow than the east metro sees, and the melt doesn't spread out on a graded lot; it channels. Under slab edges, along foundation backfill, through old utility trenches, the same paths every year. Each season the channels widen a little. Add clay shrinking in a dry summer and you've got two mechanisms excavating under your concrete at once, neither one visible from above.
Why bridging slabs fail suddenly instead of slowly
A slab over a void looks fine until it doesn't. Concrete is strong in compression and weak in bending, so a bridging slab holds its shape until a load finds the unsupported span. Then it cracks and drops in one event: a delivery truck on the apron, a full trash bin rolled over the same spot, sometimes just a hard freeze. The homes through Green Mountain and Applewood have fifty-plus-year-old slabs with decades of accumulated washout beneath them, which is why we treat a hollow tap on an older Lakewood slab as a schedule-it-now finding, not a watch-it item.
What filling costs next to what sinking costs
We quote void fill by volume, free and in person. Trevor will tell you at the estimate how long the crew needs and when the slab goes back in service. Held up against what the void becomes if you wait, the math is lopsided:
- Fill the void now: the small job, slab stays at grade
- Wait for settlement: the fill plus a full lift
- Wait for the crack: possibly a replacement pour at many times the price
The slurry we pump, water and sandy loam soil, flows to the far corners of the cavity and cures into a dense, stable fill, so the washed-out zone ends up more erosion-resistant than it was originally. If the slab has already begun to drop, we can pressure-pump the same material and lift while we fill; the difference between the two jobs is explained on our main void fill page.
Cut off the supply line
Filling a void without stopping the water that dug it is half a repair, so we finish every Lakewood job with a walk around the lot. More often than not the culprit is obvious once you know to look: a downspout ending at a slab corner, a splash block aimed uphill, a low spot funneling melt along the garage. Extend a downspout well past the slab and you've retired the excavator that was working under your concrete. On steeper Green Mountain lots we'll sometimes suggest a simple gravel trench along the uphill slab edge to intercept runoff before it dives underneath; it's a weekend project that protects a professional repair.
Book the tap test
If something on your property sounds hollow, or you just want the slabs checked after this winter's melt, call (303) 526-2222. Trevor comes out in person, taps every slab you're worried about, and quotes only what actually needs filling. Free estimate, a written number, and a company that's been doing this since 1988.