What Big Dry Creek clay does two floors down
The expansive clay pockets that run through Westminster's Big Dry Creek drainage don't stop at your foundation wall. The same soil sits under the basement slab, and it behaves down there the way it behaves under driveways: swelling in wet years, shrinking in dry ones. Under a basement floor, it's the shrink half of the cycle that does the damage. A run of dry seasons pulls the clay down and away from the underside of the slab, the concrete bridges the gap for a while, and then a section lets go. You notice a dip along the perimeter, a crack tracking the expansion joint, or a floor drain that used to be the low point and suddenly isn't.
Westminster's fast melts add a wrinkle. When the snow disappears in a day or two, the ground beside the foundation takes on a season's worth of water almost at once, and clay that has saturated and re-dried for decades gets less predictable with every cycle. In the 1960s through 80s neighborhoods, that's a lot of cycles on first-generation slabs, and plenty of those floors are moving now.
Lifting the floor without wrecking the basement
Every other bid you'll get for a settled basement floor starts with demolition: tear out the flooring, jackhammer the slab, haul rubble up the stairs, re-pour, wait. We skip all of it. Mudjacking works through 1-1/2" holes drilled in the slab, one every 4 to 6 feet across the settled area. We pump slurry through them until the void below is packed and the floor reads level, then patch the holes flush. Finished walls stay finished. We keep the holes away from the perimeter and tarp the route from the door before the first one is drilled. Carpet or tile over the work area comes up first, and flooring goes right back over the patches once they cure.
The mix is water and sandy loam soil. It cures inert, with no foam chemistry and nothing to off-gas into the room your family uses.
Floor problem or foundation problem? We check first.
Before anyone talks price, Trevor walks the basement looking for signs the walls are moving: stair-stepped cracks at the corners, upstairs doors that quit latching, windows binding in their frames. If those show up, we'll tell you to bring in a structural engineer before spending a dollar on the floor, because a lifted slab under a shifting foundation just hides the real problem. That answer has cost us jobs. You'll get it anyway.
Cost, timeline, and what you skip
- Priced by lift area and how much void has opened underneath, quoted free and in person.
- Timeline set by access, covered at the estimate.
- What you avoid: demolition inside a finished house, a re-pour, weeks of cure time, and a bill that starts around five figures.
Winter is actually a good month to book this one. The work is indoors, the slurry cures fine in cold weather, and January calendars are far easier to get on than May's.
What a lift won't do, said plainly
Raising the slab levels the floor. It doesn't waterproof it. If groundwater is coming through the cove joint or up through cracks during those fast Westminster melts, that drainage problem needs fixing first or alongside, because the water that pools is often the same water that dug the void. Trevor points out what he sees during the estimate either way, and he'd rather send you to the right fix than pump slurry under the wrong one.
Start with a walk-through
One visit answers the whole question. Trevor checks the walls, runs a level and a steel rod across the floor, and tells you whether you've got a slab worth lifting, a void worth filling, or a structural question that comes before either. If it's the first two, the written number comes on the spot. You can see finished floors on our work page, read more at our basement floor leveling page, or call (303) 526-2222 for the free in-person estimate.