Why is my driveway sinking near the garage?
Because the soil right outside the garage door is usually the weakest soil under the whole driveway. It’s backfill that was dug out and pushed back in when the foundation was built, and it often keeps settling for years. Roof water dripping at the door and vehicle weight at the edge add to it. The slab there is often liftable back to the garage floor with polyurethane foam.
What it looks like
This problem has a very recognizable set of symptoms.
- A bump or drop right at the garage door when you drive in
- A gap under the closed garage door, with daylight or leaves getting in
- A wide, open joint where the driveway meets the garage floor
- Water or snowmelt running into the garage
- The driveway panel sloping toward the garage instead of away
- A crack running parallel to the garage door a few feet out
Why it happens right there
Foundation backfill
When a house is built, the ground around the foundation is excavated, the foundation is poured, and the soil is pushed back into the gap. That backfill is looser than the undisturbed ground farther out, and unless it was compacted carefully in layers, it keeps settling. The garage door is where the driveway sits right on top of it.
Roof water
Many garages have a roof edge right above the door. Without gutters, or with gutters that overflow, water drops in a line right on the apron and the joint. That water gets under the slab and softens the backfill.
Weight at the edge
Every vehicle stops, turns and accelerates at the garage door. That puts the heaviest, most frequent load right at the edge of the slab where the support is weakest.
Water flowing in the wrong direction
Once the slab tips toward the garage, water runs toward the joint instead of away. The problem feeds itself.
Is it the apron or the driveway?
It helps to know which slab moved.
| What you see | Likely cause |
|---|---|
| Drop right at the door, the first slab out is tipped toward the garage | The apron settled on the foundation backfill |
| Lip a few feet out, the apron looks fine | The next driveway panel settled, often over a utility trench |
| Both slabs dropped | Settlement across the backfill zone. Usually lifted together |
| Cracks inside the garage too | The garage floor may be moving. That needs a closer look |
If it’s the apron, garage apron leveling covers the repair in detail. If it’s farther out, driveway leveling covers panels across the whole driveway.
Why it’s worth fixing soon
A gap under the garage door lets in cold, water, dust and pests. Water that runs into the joint washes out more backfill, so the slab keeps dropping. And the drop at the door is often exactly where people walk carrying things into the house. The longer it goes, the more likely the slab cracks, and a cracked slab is a harder lift.
How it’s fixed
Sunken
Concrete has settled or lost support.
Lifted
Polyurethane foam is injected beneath the slab.
Level
The slab is raised toward its proper position, and the void space is stabilized.
We drill small ports in the settled slab and inject polyurethane foam beneath it. The foam fills the voids left in the backfill and raises the slab back toward the garage floor, keeping a slight slope away from the door. The joint can then be sealed to keep water out. How foam concrete lifting works explains the steps. Dealing with roof water at the door, like adding or fixing a gutter, helps keep it from coming back.
Can yours be lifted?
If the slab is whole or in a few large pieces, it usually can. Can sunken concrete be lifted? explains what we check. For more on the causes, see why does concrete sink?.
Questions about driveways sinking at the garage
Is my driveway sinking or is my garage floor rising?
Almost always the driveway is sinking. The garage floor sits on the foundation and rarely moves, while the driveway rests on backfill that settles.
Will a gutter above the garage door help?
It can. Roof water dripping onto the apron and joint is a common contributor. Directing it away helps the slab stay put after it's lifted.
Does a sinking driveway at the garage mean foundation problems?
Usually not. The driveway and the house foundation are separate. The driveway settles because the soil under it was disturbed during construction.
My house is only a few years old. Is it normal?
It's common with newer homes because the backfill around the foundation is still compacting. It's still worth fixing if it's causing a gap, a bump or water in the garage.