Cracked or sunken concrete in Las Vegas can often be lifted with cement slurry or polyurethane foam, sealed, patched or resurfaced. Replacement is better when slabs are badly broken or crumbling. In the valley, water from irrigation, leaks or downspouts is a leading cause, so fixing it is part of any lasting repair.
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Not every cracked or sunken slab in Las Vegas needs to be torn out. Concrete can often be lifted, sealed, patched or resurfaced for less disruption than a replacement. The key is understanding why it failed, and in the desert the answer very often involves water reaching soil that wasn't built to handle it.
Why concrete cracks and sinks in the Las Vegas Valley
- Irrigation and leaks. Drip lines, sprinklers, pool leaks and downspouts that wet the soil next to or under a slab are common causes of settlement.
- Collapsible and expansive soils. Some valley soils settle when soaked for the first time, while finer clay soils can swell and shrink. The Nevada Bureau of Mines and Geology has mapped collapsible soil potential and other hazards across the valley.
- Loose backfill. Soil placed against foundations and around utility trenches can settle over the years.
- Sulfate attack. Sulfate-bearing soils can slowly damage concrete that wasn't made with sulfate-resistant cement, leaving a soft, crumbling surface near the ground.
- Heat and fast drying. Concrete that dried too fast during a hot pour can show early shrinkage and surface cracking.
- Ground movement. The valley has mapped earth fissures and subsidence-related faults in some areas. These are uncommon on a given lot, but if cracks line up across several slabs, walls and the street, mention it to the contractor.
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: an expanding foam is injected through smaller holes. It is light and cures quickly.
- Crack and joint sealing: flexible sealants keep water and dust out.
- Patching: repair mortars fix spalled spots, though patches rarely match.
- Resurfacing: a thin cement-based overlay renews a worn but sound surface.
- Section replacement: badly broken panels are cut out at joints and repoured.
Fix the water first
Lifting a slab without stopping the water that undermined it usually buys only a short reprieve. Check irrigation for leaks, cap or move emitters near slabs, extend downspouts, and have a pool checked if settlement is near the deck. Then decide whether to lift or replace.
Trip hazards
An offset joint on a walkway is a common fall risk. Contractors can lift the low side, grind the high edge or replace the panel. If the hazard is on a public sidewalk, check with your city, or Clark County Public Works in unincorporated areas, before work is done.
When it might be structural
Cracks in flatwork are usually not structural. But cracks in stucco that grow, doors and windows that start sticking, gaps between the house and the slab or block wall, or cracks in the home's foundation can point to foundation movement. In those cases, an evaluation by a Nevada-licensed structural or geotechnical engineer is the right first step.
Questions to ask
- What caused the problem, and how will the repair address it?
- Will you lift, patch or replace, and why?
- What will the drill holes or patches look like?
- Is there a warranty if the slab settles again?
Not sure which way to go? Read why concrete cracks on Las Vegas soil, or mark your request urgent and request a concrete repair contractor.
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Frequently asked questions
Is mudjacking or foam lifting better?
Both can lift sunken slabs. Slurry lifting is a long-established method; polyurethane foam uses smaller holes, is lighter and cures quickly. The right choice depends on the slab, the voids and the contractor's experience.
Why is the surface of my old concrete crumbling near the ground?
Possible causes include sulfate attack from the soil, repeated wetting and drying with hard irrigation water, or a weak surface from poor curing. A contractor can look at the pattern and recommend resurfacing or replacement.
Could cracks in my yard be an earth fissure?
Earth fissures exist in parts of the Las Vegas Valley, but they're uncommon on any one property. If cracks line up across slabs, walls and the street, mention it and consider having a geotechnical engineer look. The Nevada Bureau of Mines and Geology has mapped fissure areas.
Sources and further reading
- Nevada State Contractors Board: license requirements
- Nevada State Contractors Board: Residential Recovery Fund
- Nevada Administrative Code 624.230: C-5 concrete contracting classification
- USA North 811 (Nevada and Northern California)
- Southern Nevada Water Authority: Water Smart Landscapes rebate
- Nevada Bureau of Mines and Geology: Subsidence in Las Vegas Valley, 1980-91
- University of Nevada, Reno Extension (Southern Nevada soils and caliche)
- Clark County Public Works: encroachment permits
- City of Las Vegas: permits and licenses
- Boulder City: driveway aprons
- American Concrete Institute (ACI)
- Portland Cement Association (PCA)