Stan's Two Projects
Same problem, different solutions.
The Garage Floor
About 120 square feet of settled slab near the foundation wall. One inch low at the worst spot. Stan parks his car there every day. He wanted minimal downtime and didn't want to look at big patched holes in his garage floor for years.
The foam contractor drilled holes about the size of a dime, injected the polyurethane, and Stan was parking on it that afternoon. Total cost: $1,200.
The Driveway
About 150 square feet of settled concrete near where it meets the garage. Similar settlement depth. But the driveway didn't need to look perfect, and Stan could park on the street while it cured.
The mudjacking contractor drilled holes about the size of a golf ball, pumped cement slurry underneath, and told Stan to stay off it for 24 hours. Total cost: $800.
The Decision Logic
The garage needed aesthetics and quick turnaround. Worth paying more for smaller holes and immediate use. The driveway needed lifting on a budget. Bigger holes were acceptable and overnight cure was fine.
Both slabs are level now. Both methods worked. The right choice depended on Stan's priorities for each location.
How Mudjacking Works
The traditional method.
The Process
Holes about 2 inches in diameter get drilled through the settled slab. A cement-based slurry is pumped through the holes under pressure. The slurry fills voids underneath and lifts the slab as more material goes in. When the slab reaches level, pumping stops and holes get patched.
The slurry is heavy. It sets solid and provides stable support.
Time and Cure
The actual lifting takes maybe an hour for a typical residential job. But the slurry needs time to cure, usually 24-48 hours before you should drive or walk on it. Stan's driveway was off-limits for a day.
Cost Range
Typically $3-6 per square foot for residential work. Stan's 150 square feet at about $5.30 per square foot came to $800. Pricing varies by location and complexity.
The Tradeoffs
Cheaper than foam. Proven technology used for 50+ years. But bigger holes, longer cure time, and the slurry adds weight to potentially weak soil. For Stan's driveway, none of these downsides mattered enough to pay more.
How Polyurethane Foam Works
The newer method.
The Process
Small holes about 5/8 inch in diameter get drilled through the slab. A two-part polyurethane mixture is injected through the holes. The chemicals react and expand, filling voids and lifting the slab. It cures in minutes.
The foam is extremely light. It won't add significant load to the soil underneath.
Time and Cure
The lifting takes similar time to mudjacking, maybe an hour. But cure time is minutes, not days. Stan's garage was ready for his car that same afternoon. The foam was fully cured by the time they finished cleanup.
Cost Range
Typically $5-10 per square foot. Stan's 120 square feet at $10 per square foot came to $1,200. More expensive than mudjacking, sometimes significantly so.
The Tradeoffs
More expensive. But smaller holes, instant cure, and no added weight. For Stan's garage where he wanted to park immediately and didn't want visible repair patches, the extra cost was worth it.
Head-to-Head Comparison
How they stack up on specifics.
Cost
Mudjacking typically costs 40-60% less than foam. For large areas like driveways and sidewalks, the savings can be substantial. Stan saved $400 using mudjacking for his driveway instead of foam.
Hole Size
Mudjacking holes are about 2 inches, roughly golf ball size. Foam holes are about 5/8 inch, smaller than a dime. After patching, mudjacking holes are more visible. On decorative concrete or interior floors, this matters.
Cure Time
Foam cures in minutes. Mudjacking needs 24-48 hours. If you need the slab usable immediately, foam is the only choice. If you can wait a day, mudjacking works fine.
Weight
Cement slurry is heavy, over 100 pounds per cubic foot. Foam is light, maybe 2-4 pounds per cubic foot. If your settlement was caused by weak soil being overloaded, adding more weight with mudjacking could cause future problems. Foam doesn't have this issue.
Water Resistance
Foam is waterproof. It won't erode or wash away if water gets underneath. Cement slurry can erode over time with water exposure. In wet areas, foam may be more durable long-term.
Precision
Foam expansion can be controlled very precisely. Experienced mudjacking operators also get good results, but foam allows finer control. For exact leveling work, foam has an edge.
Best Situations for Each
Where each method excels.
Choose Mudjacking When
Budget is a priority. You're lifting large outdoor areas like driveways or pool decks. You don't need immediate use. The underlying soil is stable and won't be affected by added weight. Aesthetics of repair patches don't matter much.
Stan's driveway fit all these criteria. Mudjacking was the smart choice.
Choose Polyurethane When
You need immediate use of the slab. The surface is interior or decorative where small holes matter. You're concerned about weak underlying soil. Water issues are present. Quick turnaround is worth paying for.
Stan's garage fit these criteria. Foam was worth the extra cost.
Either Works When
Many situations could go either way. A settled porch step, a section of sidewalk, a garage threshold. Both methods can handle these. Your choice might come down to which contractor is available, what method you're more comfortable with, or simply price.
Limitations of Both
Neither method is perfect.
Cracked Slabs
Both methods lift slabs but neither repairs cracks. If your slab is broken into pieces, lifting might separate the pieces further. Badly cracked slabs might need replacement rather than lifting.
Stan's slabs had minor cracks that the contractor said wouldn't affect lifting. Severe cracking is different.
Root Cause Issues
Lifting treats the symptom, not necessarily the cause. If settlement happened because of drainage problems, soil issues, or ongoing erosion, the slab might settle again. Stan addressed drainage as part of his project to prevent recurrence.
Void Size
Extremely large voids might exceed what injection can practically fill. If a slab has settled many inches with huge gaps underneath, other approaches might be needed. Stan's one inch of settlement was well within normal range for injection lifting.
Not Structural Repair
Slab lifting is separate from foundation repair. If your slab settled because foundation walls are failing, lifting the slab doesn't fix the wall problem. Make sure you're treating the right issue.
Finding a Contractor
How Stan chose his contractors.
Specialists vs. Generalists
Stan got quotes from a mudjacking specialist and a foam specialist, plus one company that does both. The specialists were more competitive in their respective methods. A company focused on one approach often has better equipment and more experience.
Get Multiple Quotes
Stan got three quotes for each project. Prices varied by about 30%. The cheapest mudjacking quote was $650, the highest was $950. Getting multiple quotes revealed the market range.
Ask About Warranty
Both of Stan's contractors offered 2-year warranties on the lift. Not long, but reasonable for this type of work. Some companies offer longer warranties. Understand what's covered before deciding.
Check References
Stan asked each contractor for references from jobs a year or more old. He wanted to know whether the lift held, not just whether the crew was pleasant. One company couldn't provide older references, which was concerning.
What Stan Would Do Differently
Lessons from his experience.
Address Drainage First
Stan fixed drainage around both slabs after lifting. He wishes he'd done it before. The contractor mentioned that without drainage improvement, the slabs might settle again. Should have been part of the plan from the start.
Consider Combination
Some jobs might benefit from both methods. Foam for interior or visible areas, mudjacking for hidden or exterior areas. Stan's two-method approach wasn't planned that way, but it worked out well.
Don't Over-Improve
Stan was tempted to get foam for everything because it seemed like the better technology. But his driveway didn't need the advantages foam offers. Paying more for benefits you won't use is waste.
Budget Correctly
Stan initially budgeted for mudjacking both areas at about $1,600 total. When he decided foam made sense for the garage, the total went to $2,000. Knowing the cost difference upfront helps with realistic budgeting.