Sunken or cracked concrete in Tampa can often be lifted with slurry or foam, sealed, patched or resurfaced. Replacement is better when slabs are badly broken. Any repair should also fix the cause, usually water washing sand from under the slab. Rapid or spreading ground settlement warrants an engineer or geologist and a call to your insurer.
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Sunken and cracked concrete is one of the most common requests we get from Tampa Bay homeowners. A driveway corner drops near the garage, a pool deck section tilts, a walkway panel settles and leaves a lip. Not every problem needs a new slab. Many can be lifted, sealed or resurfaced, as long as the repair also deals with what caused the damage.
Why concrete sinks and cracks here
- Washed-out sand. Runoff from roofs, sprinklers and storms can carry sand out from under slab edges, leaving voids.
- Poorly compacted fill. Soil backfilled around a new house or pool may settle for years if it wasn't compacted.
- Leaking pipes. A broken irrigation, water or drain line under a slab can wash out support quickly.
- Organic material. Buried roots, stumps or construction debris decompose and leave soft spots.
- Tree roots. Roots lift slabs from below, especially near live oaks.
- Karst geology. Much of the Tampa Bay region sits over limestone, and the Florida Geological Survey describes sinkholes forming where sediment drains into voids in that rock. Most sunken slabs have ordinary causes, but ground subsidence is a possibility here that it isn't in many places.
Repair options
- Slab lifting. A sunken slab that's still in one piece can be raised by injecting a cement-based slurry or polyurethane foam underneath. Foam uses smaller holes and cures quickly; slurry is the older method. Both also fill voids.
- Crack sealing. Flexible sealants keep water out of cracks so it doesn't keep washing sand from below.
- Patching and resurfacing. Thin cement-based overlays can renew a worn or stained surface if the slab underneath is sound.
- Grinding. A small lifted edge on a walk can sometimes be ground down to remove a trip hazard.
- Section replacement. Badly broken panels are cut out at the joints and re-poured.
Fix the cause
A lifted slab will sink again if water keeps washing sand from underneath. A good repair plan includes redirecting downspouts, adjusting sprinkler heads, sealing joints and cracks, and checking for leaks if the settling came on suddenly. If a leaking pipe is suspected, have it found and fixed before the slab is lifted.
When to get more than a concrete contractor
If settling is fast, a depression is spreading across the yard, a hole has opened, or you see new cracks in the house walls or doors that suddenly stick, stop and have it evaluated by a licensed engineer or professional geologist. Contact your insurance company, since Florida policies handle sinkhole and ground collapse claims in specific ways. Our guide on sinking concrete and sinkholes in Tampa Bay explains the warning signs.
Repair or replace?
Repair makes sense when cracks are narrow, the slab is mostly intact and the surface is sound. Replacement is usually better when cracking is widespread, sections have shifted in different directions, or the surface is crumbling. A contractor who sees the slab in person can tell you which you're dealing with.
Questions to ask
- What do you think caused the settling?
- Slurry or foam, and why for this slab?
- How will you fill the injection holes, and will they show?
- What will keep it from settling again?
- What does the warranty cover?
Have a sunken or cracked slab? Request a repair contractor and include photos with something in the shot for scale.
See how it works
Frequently asked questions
Is my sunken driveway a sinkhole?
Usually not. Most sunken slabs come from washed-out sand, poorly compacted fill, decaying organic material or leaking pipes. The Florida Geological Survey notes that only a licensed professional can verify a sinkhole. If settling is spreading or a hole opens, keep people away and contact your insurer.
Is foam or slurry lifting better?
Both can raise sunken slabs and fill voids. Foam uses smaller holes and cures quickly; cement slurry is the long-established method. The right choice depends on the slab, the voids and the contractor's experience.
Will a lifted slab sink again?
It can if the cause isn't fixed. Redirect downspouts, aim sprinklers away, seal joints and cracks, and repair any leaking pipes so water stops washing sand from beneath.
Sources and further reading
- American Concrete Institute (ACI)
- Portland Cement Association (PCA)
- UF/IFAS Extension: Spodosols in Florida (EDIS SS655)
- Florida Geological Survey: Sinkhole FAQ
- Florida Museum of Natural History: Sinkholes
- Florida DBPR, Construction Industry Licensing Board
- Hillsborough County Contractor Licensing
- Pinellas County Contractor Licensing
- City of Tampa Right-of-Way Permits
- City of St. Petersburg Right-of-Way Permit Application
- City of Clearwater Right-of-Way Permit Form
- Southwest Florida Water Management District
- Sunshine 811: When Can I Dig?