How to Fix a Sinking Driveway (Without Full Replacement)

Why Driveways Sink

Concrete doesn't sink—the ground underneath does. Common causes:

• Soil erosion: Water washes away soil from under the slab
• Poor compaction: Fill dirt wasn't compacted properly during construction
• Organic decay: Buried roots or organic material decomposed
• Water drainage issues: Downspouts or runoff undermining the base
• Tree roots: Roots pushed up concrete, then died and left voids

Two Lifting Options

Mudjacking (Slabjacking)

Holes are drilled through the concrete, and a cement/sand/water slurry is pumped underneath to fill voids and raise the slab.

• Cost: $3-6 per square foot
• Pros: Cheapest option, widely available, proven method
• Cons: Heavy material can cause re-settling, larger holes (1-2"), can crack weak concrete
• Best for: Budget repairs, thick slabs, minor settling

Polyurethane Foam Injection

Small holes are drilled and expanding polyurethane foam is injected. The foam expands to fill voids and lift the slab.

• Cost: $5-10 per square foot
• Pros: Lightweight (won't cause re-settling), smaller holes (5/8"), faster curing, waterproof
• Cons: More expensive, not available everywhere, foam isn't adjustable once set
• Best for: Long-term fixes, areas with water issues, thinner slabs

Cost Comparison: Lift vs Replace

Method	Cost/Sq Ft	400 Sq Ft Driveway
Mudjacking	$3-6	$1,200-2,400
Foam Injection	$5-10	$2,000-4,000
Full Replacement	$8-12	$3,200-4,800

Lifting saves 30-60% compared to full replacement.

When Lifting Won't Work

Lifting isn't always possible. You need replacement if:

• Concrete is severely cracked: Multiple large cracks, broken into pieces
• Slab is too thin: Under 3 inches won't handle lifting pressure
• Ongoing drainage issues: If water keeps undermining, lifting is temporary
• Rebar is exposed or rusted: Structural integrity is compromised
• Settlement exceeds 4-6 inches: Extreme settling often means bigger soil problems

How Long Does Lifting Last?

Mudjacking: 5-10 years on average. The heavy slurry can compress underlying soil over time. Foam injection: 10-20+ years. The lightweight foam doesn't add soil pressure. Both can fail if the underlying cause (drainage, erosion) isn't addressed.

Can I DIY Driveway Lifting?

No. Both methods require specialized equipment (pumps, injection guns) and experience knowing how much material to inject. Over-injection cracks the concrete. Under-injection leaves it unlevel. This is a job for specialists.

Will Lifting Fix Cracks?

No. Lifting raises the slab—it doesn't repair cracks. Cracks will still be there after lifting and should be sealed separately. If cracks are the main problem, lifting won't help.

Key Takeaways

• Sinking driveways can be lifted for 30-60% less than replacement
• Mudjacking: $3-6/sq ft, cheaper but heavier, may re-settle
• Foam injection: $5-10/sq ft, lighter, lasts longer, waterproof
• Not an option if concrete is severely cracked or too thin
• Fix drainage issues first or lifting will be temporary
• Both methods take a few hours; drivable same day