What a century of Denver clay does under a basement
Plenty of Denver basements were dug before the Great Depression. The brick bungalows of Wash Park and Berkeley sit over cellars that have since become bedrooms and rec rooms, and their floor slabs, whether original or repoured decades later, rest directly on Denver Formation claystone. That clay gives up moisture in dry years and shrinks as it goes, pulling away from the underside of the slab. The floor bridges the gap for a while. Then a corner drops, a crack tracks across the room, or the floor drain turns into the high point and laundry water heads for the wall instead.
Postwar ranches and new infill run into the same physics. The clay doesn't care what year the house went up. It cares whether the moisture under your floor still matches what it held the day the slab was poured.
Dry summers open the gap; spring melt finds it
Denver's weather works basements from both ends. Drought summers shrink the claystone and open space under the slab. Then the heavy wet snows of March and April melt fast, saturate the soil around the foundation, and drive moisture toward the driest dirt on the lot, which is the dirt under your house. Water moving beneath a slab carries fines along with it and resettles them unevenly. Stack up enough of those cycles and the floor you finished ten years ago isn't flat anymore.
Raising a floor through holes the size of a golf ball
Our fix involves no jackhammer and no rubble going up the stairs. We drill 1-1/2" holes through the slab, one every 4 to 6 feet across the settled area, and pump a slurry of water and sandy loam soil into the space below. The slab comes back up to grade, the holes get patched flush, and flooring goes right back over them.
- Time on site depends on access and lift area; Trevor covers it at the estimate.
- Trevor will tell you at the estimate how soon the floor takes foot traffic.
- Finished walls stay finished. Holes stay clear of the perimeter and everything gets tarped before the first bit of drilling.
- The mix carries no solvents and no foam chemistry, which matters in the room your kids camp out in.
- Winter books easily. The work is indoors and the slurry cures fine in the cold.
The check we run before we'll quote anything
A sunken basement floor and a moving foundation wall can look alike from the top of the stairs, and only one of them is our job. During the estimate we look for stair-step cracking at wall corners, upstairs doors that quit latching, and windows binding in their frames. Those signs mean structural engineer, not slab lift, and we'll tell you so plainly and leave without quoting. Pumping under a floor while the walls move just buries the evidence, and a company doesn't last in this town since 1988 by making that trade.
Denver basement lift pricing
Basement floor lifts are priced by area and how much space has opened underneath, quoted free and in person. Against the alternatives that's the small option by a wide margin: breaking out and repouring a slab inside a finished basement lands well into five figures once flooring and trim are counted, and underpinning starts higher still. When the floor is the problem and the walls are sound, lifting fixes it without remodeling your basement on the way through.
The number is written, and the work is done with the same truck and custom-batched slurry we bring to every job. In basements that matters: careful hole placement, clean tarping, and a floor that's soon ready for flooring again all come from repetition, not luck. If you want the background on why the ground hollows out in the first place, we wrote up how voids form under concrete.
Start with the walk-through
Trevor brings a level and a steel rod, walks the floor, checks the walls, and hands you either a written number or an honest referral to an engineer. Call (303) 526-2222 or request the free estimate. He can typically look within a few days.