How to Fix a Sinking Section of Driveway (Causes + Cost)

TL;DR: A sinking driveway slab almost always means the soil or gravel base underneath has washed out or compacted unevenly, usually from poor drainage. Most sunken sections can be raised back to level with mudjacking ($3-$6 per square foot) or polyurethane foam injection ($5-$25 per square foot) instead of a full replacement, which runs $8-$18 per square foot. Fix the water source first, or the same spot will sink again within 2-3 years.

_Last reviewed: July 2026 · 7 min read_

A dip in your driveway that catches rainwater and makes your car dip and bounce isn't cosmetic. It's a sign the ground under that slab has gone somewhere, and it usually keeps going somewhere until you deal with the cause, not just the surface.

Okoniq Property Hub helps you log driveway repairs, note which section sank and when, and track whether a fix actually holds over the following seasons.

Why does a driveway sink in just one section?

A section sinks when the soil or gravel base under that specific slab loses volume, usually from water erosion, poor compaction from the original pour, or a buried pipe or root that shifted the ground. Concrete itself doesn't compress. When it drops, the support underneath it is gone.

The most common cause on residential driveways is water running under the slab from a downspout, a sloped yard, or a cracked joint that lets rain seep in and wash out fine soil particles, a process called erosion. Over 5-10 years this can hollow out several inches of space under a slab edge without any visible sign until the concrete finally settles into the void. If you've also noticed grading problems nearby, 5 drainage jobs you're forgetting before rainy season covers the fixes that stop this at the source.

Poor original compaction is the second cause. Builders are supposed to compact the gravel base in 4-6 inch lifts before pouring, and skipping this step means the ground settles naturally over the first 2-5 years of the driveway's life, often unevenly. Tree roots and freeze-thaw heaving are less common but do the same thing: they change the volume of what's holding the slab up.

Is mudjacking or foam lifting the better fix?

For most sunken driveway sections, polyurethane foam lifting is the better fix in 2025 because it's faster, lighter, and doesn't add extra weight that could cause future settling. Mudjacking is the older method, using a cement-based slurry pumped under the slab through small drilled holes to raise it back to level.

| Factor | Mudjacking | Polyurethane Foam | |---|---|---| | Cost per sq ft | $3-$6 | $5-$25 | | Cure time | 24-48 hours | 15 minutes | | Hole size | 1-2 inches | 5/8 inch | | Added weight | Heavy slurry mix | Near-weightless foam | | Typical lifespan | 5-10 years | 10-15+ years |

Mudjacking costs less upfront but adds hundreds of pounds of material under the slab, which can be a problem if the underlying soil is already weak. Foam expands to fill voids and adds almost no weight, which is why it's become the standard choice for driveways over soft or previously-eroded soil. Either method takes a few hours per section and doesn't require breaking up the existing concrete, which is why both are cheaper than replacement.

How much does it cost to fix a sinking driveway?

Fixing a sunken section typically costs $500-$1,800 with foam or mudjacking, compared to $3,000-$10,000+ for tearing out and repouring the same area. A single-car driveway section (roughly 10x20 feet) at $5-$10 per square foot for foam lifting lands around $1,000-$2,000, while a similar mudjacking job runs $600-$1,200.

Full replacement only makes sense when the concrete itself is cracked into multiple pieces, when more than 30-40% of the driveway is affected, or when the slab is over 25-30 years old and showing surface spalling on top of the sinking. If the sinking is happening near your house foundation rather than out in the driveway, get that checked separately. 5 signs water is undermining your foundation explains what to watch for when the same erosion problem is closer to the structure.

Will the driveway just sink again after it's repaired?

Yes, it will sink again within 2-3 years if you don't fix whatever caused the erosion or settling in the first place. Lifting the slab back to level does nothing to stop water from continuing to wash out soil from underneath it.

Before or right after the repair, redirect any downspout draining within 6-10 feet of the sunken section, using a splash block or 4-inch PVC extension to carry water at least 5 feet away. Check that the driveway still slopes away from the house at roughly a 1/4-inch-per-foot pitch, and reseal any cracked expansion joints with polyurethane concrete caulk so surface water can't seep down through them. If your yard has a broader grading issue causing water to pool near hardscape, a retaining wall or regrading job may be the real fix, and 5 signs your retaining wall is about to fail is worth a read if you have one nearby that's holding back the slope.

Should you worry about a sinking driveway spreading to the foundation?

You should check the foundation if the sinking section is within 10-15 feet of the house, because the same soil erosion or drainage problem can migrate toward the structure over time. This is more common than people expect, especially on lots with a slight grade toward the house.

Walk the foundation line closest to the sunken driveway area and look for new cracks, gaps at the sill, or soil pulling away from the wall. 5 foundation checks you're forgetting every spring gives you a quick walkthrough you can do in 15 minutes. Catching a shared drainage problem early here can save you from a repair that's 5-10x more expensive than the driveway fix alone.

FAQ

Can I fix a sinking driveway myself?

DIY mudjacking kits exist but are difficult to use correctly without professional equipment for pressure control, and a botched injection can crack the slab further. Most owner-operators hire a concrete leveling contractor for $500-$1,800 rather than risk a DIY attempt on a slab they plan to keep for years.

How do I know if it's the base sinking or the concrete itself failing?

If the surface is intact but tilted or dipped as one solid piece, it's the base underneath that's gone. If you see the slab cracked into separate pieces at different heights, the concrete has failed and needs replacement rather than lifting.

Does homeowners insurance cover a sinking driveway?

Standard homeowners policies typically exclude gradual settling and erosion, since these are considered maintenance issues rather than sudden covered events. Coverage sometimes applies if the sinking was caused by a specific covered peril like a burst underground pipe, so check your policy language before assuming it's excluded.

How long does a foam lifting repair take?

Most single-section jobs take 1-3 hours, and the foam cures enough to drive on within 15 minutes, though contractors often recommend waiting a few hours as a precaution. This is one of the biggest advantages over mudjacking, which needs 24-48 hours before the driveway can handle vehicle weight again.

Is a sinking driveway a sign of a sinkhole?

True sinkholes are rare outside specific geologic regions with limestone or karst bedrock, and most residential driveway sinking is erosion or compaction, not a sinkhole. If the depression is growing rapidly, appeared suddenly without heavy rain, or is accompanied by a hollow sound when you tap the surface, get a geotechnical inspection before doing any repair.

This is educational information, not engineering or legal advice. Call a licensed concrete contractor or geotechnical engineer if the sinking is severe, near your foundation, or growing quickly.