A settling basement slab can be lifted from inside the house — no demolition, no excavation. Here's how interior lifting works, why foam is the indoor method, and how to tell a slab problem from a foundation problem.
Many homeowners assume a sinking basement floor means tearing it out — jackhammers, dumpsters, weeks of chaos. It doesn't. Interior slab lifting brings compact injection equipment through a standard doorway, drills small holes through the slab, and pumps polyurethane foam underneath to fill voids and raise the floor. The crew works around your furnace, water heater, and storage; most basement lifts finish in a day; and you walk on the floor immediately after.
The process is the same principle as exterior lifting — see how concrete lifting works — adapted for indoor logistics. Smaller rigs, tighter dust control, ventilation during the injection, and drop cloths everywhere. A professional crew leaves the basement cleaner than they found the work area.
Mudjacking can be done indoors, but it's the wrong tool for the job in most basements:
| Factor | Polyurethane foam | Mudjacking |
|---|---|---|
| Equipment | Compact rig — fits through doorways, works room to room | Heavy slurry truck outside + long hoses through the house |
| Weight on weak soil | Very light — won't re-compress the soil that failed | Heavy — a real concern under interior slabs on soft fill |
| Mess | Contained process; small holes, quick cleanup | Slurry is mud — more dust, more cleanup, more disruption |
| Precision | Fine control — important around drains, plumbing, and thickened edges | Coarser |
| Use after | Immediately | 24–72 hours |
On cost, the published ranges still apply — $5–$25/sq ft for foam, $3–$8 for mudjacking — but interior foam jobs often land efficiently because the areas are smaller than a driveway and the crew moves fast indoors. The method comparison has the full breakdown.
Note the pattern: water is either the cause or the accelerant in most cases. As with exterior settlement, fix the drainage alongside the lift or expect a repeat performance.
This is the most important section on this page. Not every basement floor problem is a lifting job. You need to know which problem you have before you call anyone:
Lifting the floor does not fix foundation walls, and no honest contractor will claim otherwise. Foundation repair is a different trade with different methods (piers, wall anchors, drainage systems) and different pricing. If you see wall symptoms, start with a foundation specialist — and be wary of any lifting company that offers to "handle" foundation movement as an add-on. The two problems sometimes share a root cause (usually water against the foundation), but they need separate diagnoses and separate fixes.
The lift fills today's voids. Keeping the slab up means managing tomorrow's water: extend downspouts away from the foundation, grade soil away from the house, fix any plumbing leaks, and seal the slab joints. Interior settlement is a water problem wearing a concrete costume — treat the water and the fix holds. More on how long lifts last.
Yes — interior slab lifting is a well-established job. Small injection equipment comes through a standard doorway, holes are drilled through the slab, and polyurethane foam is injected to fill voids and raise the floor back to level. No demolition, no jackhammers, no concrete trucks in your driveway. Most basement lifts are done in a day.
Three reasons: size, weight, and mess. Foam equipment is compact enough to work indoors; mudjacking needs a heavy slurry truck parked outside with long hoses run through the house. Foam is dramatically lighter — important when the soil under an interior slab is already weak. And foam is a contained chemical process, while slurry is, well, mud: more dust, more cleanup, more disruption to a finished or semi-finished basement.
The same culprits as exterior settlement, working unseen: poorly compacted fill under the slab, soil washed out by a plumbing leak or exterior drainage dumping against the foundation, and Utah's expansive clay soils shrinking during dry periods. Interior slabs are also thinner and more lightly reinforced than exterior flatwork, so they show settlement sooner. Utah soil behavior explains the underlying mechanics.
This is the critical distinction. A settling slab: the floor drops or cracks but the foundation walls look fine — no bowing, no stair-step cracking in block walls, no doors sticking on the main level. A foundation problem: walls bowing inward, horizontal cracking, stair-step cracks in masonry, gaps at the top of walls, or sticking doors and windows upstairs. Slab settlement is a lifting job; foundation movement is a foundation specialist's job. If you see wall symptoms, call a foundation contractor first — lifting the floor won't fix the walls.
No — and be suspicious of anyone who says it will. Floor lifting addresses the slab only. Wall cracks, bowing, or shifting are foundation issues with different causes and different fixes (piers, wall anchors, drainage correction). A reputable lifting contractor will tell you this themselves and refer you to a foundation specialist if they see wall symptoms. The two problems sometimes share a cause — usually water — but they need separate solutions.
Far less messy than you'd expect. The work is drilling small holes and injecting foam — the crew should lay drop cloths, use dust control at the drill, and clean up the injection points the same visit. Cured polyurethane foam is inert; during installation there's a brief odor from the chemical reaction, so the crew should ventilate the space while they work. If anyone in the household is chemically sensitive, mention it when booking so the crew can plan ventilation and scheduling accordingly.
Same published ranges: $5–$25 per square foot for foam (the usual interior method), $3–$8 for mudjacking. Interior jobs sometimes price slightly higher per square foot than exterior because of the logistics — carrying equipment inside, working around finished space, dust control — but the job is typically smaller in area than a driveway. As always, get the written quote before work starts.
Related reading: Polyurethane foam leveling · Why concrete settles in Utah · Garage floor repair
Describe what you're seeing — floor only, or walls too? A local specialist will tell you honestly whether it's a lifting job or a foundation referral.