A drop between the garage floor and the driveway means the apron slab has sunk, usually because backfill or washed-out soil under it settled. We lift the apron back up to meet the garage floor with polyurethane foam, then seal the joint. It's often a two-hour job, and you can park on it the same day.
By Rob Diederich, owner · Updated
Common drop
1 to 3 inches
Time on site
About 2 hours
Park on it
Same day
Warranty
Written warranty
The apron comes back flush with the garage floor and pitches water away from the door. Drag the slider.
Why the apron sinks first
The garage floor sits on the foundation and its footings. The apron right outside sits on the soil that was dug out for the foundation and pushed back in. That fill settles over the years, water from the roof and the driveway soaks into it, and the apron drops away from the garage while the garage floor stays put.
Under the slab: foam fills the hollow, the apron comes back flush with the garage floor, the puddle drains off and the joint is sealed. Drag the slider.
Settling backfill
The soil pushed back against a new foundation is rarely compacted well. Anything sitting on it settles for years after the house is built.
Fix: Foam fills the voids and stiffens the zone under the slab without adding weight.
Water washout
Roof and downspout water runs into open joints and carries fine soil out from under the slab. The slab drops into the hollow.
Fix: We seal the joints, and point out downspouts that need extending.
Freeze-thaw
Clay-heavy Green Bay soil holds water. Every winter it freezes, swells and thaws softer, loosening the base a little more each year.
Fix: Sealed joints keep water out of the base, which is what freezes.
Problems a sunken apron causes
✓A lip you feel every time you drive in, and that catches snowblowers and shovels.
✓Water and slush that run back toward the garage door instead of away from it.
✓A garage door seal that no longer meets the concrete, letting in water, cold air and mice.
✓A trip hazard for anyone walking in and out of the garage.
How we fix it, step by step
1Use the garage floor as the targetThe garage floor sits on the foundation and didn't move, so it's the reference. We set the apron to meet it, pitched away from the door.
2Drill 5/8″ holesPenny-sized holes go through the slab a few feet apart, kept off the edges and corners where concrete is weakest.
3Inject and lift, door edge firstFoam fills the void under the apron, then each short shot lifts it. We start along the low edge by the door so the apron rotates up flush instead of rocking.
4Patch and seal the garage jointHoles are grouted, and the joint between the garage floor and the apron gets flexible sealant. That joint is where the water got in.
Illustrations, not to scale. Most residential jobs take a few hours, and you can walk on the slab when we pack up.
Planning a garage floor coating? Lift the apron first. A level transition makes the coated floor look finished and keeps water off it.
Why lift the apron instead of replacing it?
The apron is the one slab you drive over every day. Replacing it closes the garage to cars for about a week, and the new slab goes back on the same backfill. Lifting fills the voids in that backfill and you park in the garage the same day.
Fraction
of what tearing out and pouring new concrete costs
Same day
Walk on it when we pack up. Drive on it in hours, not a week.
No demo
No jackhammers, no dumpster, no torn-up lawn or landscaping.
5/8″ holes
Penny-sized and patched flush. No new slab that won't match.
Stays up
Foam adds almost no weight and doesn't wash out like soil.
Warranty
Written, and spelled out in your quote before you approve it.
Replace
tear out + pour
Demo
Base
Pour
Curing: no cars for about a week
Lift
foam, one visit
Done in a few hours. Use it the same day.
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 9
Day 10
Replacement timing is typical; a contractor's schedule and the weather can stretch it. New-concrete cure times from Concrete Network.
What it costs
Most garage apron repairs are one to three sections, so they often land near the job minimum. Full details are in the leveling cost guide.
Your price, without a sales visit
Send three photos and a tape-measure shot. You'll get a firm price by text within 24 hours.
Why is there a drop between my garage and driveway?
The garage floor rests on the foundation, but the driveway apron rests on backfill from when the house was built. That fill compacts and washes out over time, so the apron sinks while the garage floor stays where it is.
Can a sunken garage apron be raised?
Yes, as long as the apron slab is still in one piece or a few big pieces. Foam is injected under it to bring it back flush with the garage floor and pitched away from the door.
Will my garage door seal properly after the apron is lifted?
In most cases, yes. Once the apron is back up to the garage floor, the bottom seal of the door meets the concrete again. If the seal itself is worn, replacing it is a cheap fix we can point out.
How do I stop water from getting under my garage slab?
Keep the apron pitched away from the door, seal the joint between the apron and the garage floor, and make sure downspouts near the garage discharge away from the driveway.
