In Colorado Springs, slabs can sink from settling backfill or heave from swelling clay. Sunken slabs can often be lifted with cement slurry or polyurethane foam; heaved panels are usually ground or replaced. Sealing joints and fixing drainage should be part of any repair, and foundation cracks call for a structural or geotechnical engineer.
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Not every damaged slab in Colorado Springs needs to be torn out. Depending on the cause, concrete can often be lifted, sealed, patched or resurfaced with less disruption than a full replacement. The catch here is that slabs can move up as well as down, and a repair that ignores why the slab moved tends to fail again.
Why concrete fails in Colorado Springs
- Swelling clay. The Colorado Geological Survey notes that clay soils in the Colorado Springs area are typically expansive to some degree, and that some local bedrock, such as the Pierre Shale, can have moderate to very high swelling potential. When that soil gets wet it swells and lifts slabs, often unevenly.
- Settling backfill. Soil placed against foundations and along driveway edges during construction can compress over time, letting slabs drop near the house and garage.
- Water. Downspouts, sprinklers and snowmelt either soak clay so it swells or wash out soil and leave voids.
- Freeze-thaw and deicers. Repeated freezing and thawing, plus deicing chemicals, cause scaling and spalling on concrete that isn't air-entrained or was finished poorly.
- Shrinkage. Some cracking is normal as concrete dries, especially where joints are too far apart.
Repair options
- Slab lifting (mudjacking): a cement-based slurry is pumped under a sunken slab through drilled holes to raise it and fill voids.
- Polyurethane foam lifting: expanding foam is injected through smaller holes. It's lightweight and cures quickly.
- Grinding: a raised edge from a heaved panel can sometimes be ground down to remove a trip hazard.
- Crack and joint sealing: flexible sealants keep water out of cracks and joints, which matters a lot on swelling soil.
- Patching: spalled spots can be patched with repair mortar, though patches rarely match.
- Resurfacing: a thin cement-based overlay can renew a scaled surface on a slab that is otherwise sound and stable.
- Section replacement: badly broken or heaved panels are cut out at joints and repoured.
Lifting works for sinking, not swelling
Lifting is meant for slabs that have dropped. It can't push down a panel that clay has heaved upward, and pumping material under a slab that's on actively swelling soil doesn't fix the swelling. For heaved slabs, the usual answers are grinding a small lip, or removing the panel, correcting the soil and water problem, and repouring. Be wary of any one-size-fits-all fix.
Fix the water first
Extending downspouts, adjusting sprinkler heads that spray slab edges, sealing joints and regrading so water moves away from the house should be part of almost any repair plan. CSU Extension's guidance on expansive soils makes the same point about keeping moisture away from foundations.
Trip hazards
An uneven joint on a walk or driveway is a common cause of falls, and ice makes it worse. If the hazard is on a public sidewalk, check with your city or town before work. In Colorado Springs, concrete work in the right-of-way needs a city concrete permit and a contractor licensed for that work.
When it might be structural
Cracks in a patio or garage floor usually aren't structural. Cracks in foundation walls, stair-step cracks in brick, interior drywall cracks or doors that suddenly stick can mean the house itself is moving, which is a known risk on expansive soil along the Front Range. Start with a structural or geotechnical engineer in those cases.
Questions to ask
- Has this slab sunk or heaved, and what's causing it?
- Will you lift, grind, patch or replace, and why?
- What drainage changes do you recommend along with the repair?
- Is there a warranty if the slab moves again?
Not sure which way to go? Read our guide to expansive soil and concrete, then request a concrete repair contractor.
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Frequently asked questions
Is mudjacking or foam lifting better?
Both can raise sunken slabs. Cement-based slurry is a long-established method; polyurethane foam uses smaller holes, is lighter and cures quickly. Neither fixes a slab that clay has pushed up, and the right choice depends on the slab and soil.
Can scaled or flaking concrete be resurfaced?
If the slab is sound and not moving, a cement-based overlay can often renew it. Scaling is commonly linked to freeze-thaw, deicers or poor finishing, so ask how to keep it from coming back.
Are cracks in my driveway a sign of foundation problems?
Usually not. But cracks in foundation walls, stair-step cracks in masonry or doors that stick can point to movement on expansive soil, and that's worth an engineer's evaluation before any flatwork repair.
Sources and further reading
- American Concrete Institute (ACI)
- Portland Cement Association (PCA)
- Colorado Geological Survey: expansive soil
- Colorado Geological Survey seminar paper on Colorado Springs and Pueblo area soils
- CSU Extension PlantTalk: Expansive Soils
- Pikes Peak Regional Building Department
- PPRBD contractor license and registration types
- PPRBD basic design information (snow loads)
- City of Colorado Springs: Engineering, Inspections, Permitting and Fees
- El Paso County Public Works: Work in the Right-of-Way Permit FAQ
- City of Manitou Springs: CGS debris flow map
- Colorado Springs Utilities: 811 before you dig
- Colorado 811: homeowners