8 min read · Updated 29 August 2026
Sinking Driveway: Causes and How to Fix It
How to work out whether your sinking drive needs a £400 local repair or a rebuild, and the three site conditions behind most subsidence in this area.
The three causes we find on site
An under built sub-base. This is the leading cause by a wide margin. A drive laid on 75mm of hardcore will hold up for a couple of years and then rut in the wheel tracks, because the load path is concentrated exactly where the tyres run.
Water washing out the fines. A leaking downpipe, a blocked gully or a drive that falls towards the house will move fine material out of the sub-base over a few winters, leaving voids. The surface then drops into them.
A void or soft spot below. Old ponds, filled trenches from utility work, a collapsed drain run, or a decayed tree stump left in place. These produce sharp, localised dips rather than the broad settlement of a weak sub-base.
Diagnose it in ten minutes
Measure the dip with a straight edge and a tape. A dip under 15mm across a wide area is usually just bedding settlement and is cosmetic. Between 15 and 40mm suggests a localised base failure. Over 40mm, or a dip with a sharp edge, points to a void or a drain collapse and needs investigating before anything is relaid.
Then press on the blocks around the dip. If they rock individually, the joint sand has gone and the interlock has failed, which is repairable. If a whole area moves as a mat when driven over, the base has gone.
Finally, look at where water goes. If the dip is exactly where the downpipe discharges or where the drive falls, you have found your cause and fixing the surface without fixing the water is money wasted.
The repair options and 2026 costs
Costs below are typical fitted prices in Hampshire and Surrey.
| Repair | Cost | Suitable when | Lasts |
|---|---|---|---|
| Lift and relay a local area | £350 - £900 | Dip under 4m², base sound around it | As long as the drive |
| Lift, rebuild base, relay | £60 - £110 per m² | Localised base failure | 15 - 20 yrs |
| Drainage correction plus relay | £900 - £2,500 | Water is the root cause | 15 - 20 yrs |
| Full excavation and rebuild | £90 - £160 per m² | Whole drive rutting or rocking | 20 - 25 yrs |
| Resin or geopolymer injection | £1,500 - £4,000 | Concrete slabs over voids | 10 - 20 yrs |
What a proper local repair involves
Lift the blocks carefully and set them aside in order so the pattern goes back correctly. Excavate the failed area to firm ground, which sometimes means going 300mm rather than the original 200mm. Compact new Type 1 in layers no thicker than 75mm, screed a fresh sharp sand laying course, relay the blocks, then compact and resand.
The two shortcuts to refuse are sand infilling the dip without lifting anything, and relaying blocks on top of the failed base. Both look correct for a season and reappear the following winter.
Preventing a repeat
Fix the water first, every time. Reconnect the downpipe into a drain rather than onto the surface, clear or resize the channel drain, and make sure the fall takes water away from the house.
Then keep the joints full of kiln dried sand so the blocks stay interlocked, and keep skip lorries and heavy deliveries off a domestic drive built for cars.
Getting it looked at
We survey sinking drives, dig a trial hole where necessary to see what the base actually is, and quote for the smallest repair that will genuinely hold. Often that is a few hundred pounds, not a few thousand.
Send a photo with a straight edge across the dip to 07538 218723 and we can usually tell you which category you are in before we visit.
Frequently asked questions
- Why is my block paving driveway sinking?
- Almost always because the sub-base was too thin or was never properly compacted, or because water has washed the fine material out of it. Localised sharp dips usually indicate a void, an old trench or a collapsed drain.
- How much does it cost to fix a sinking driveway?
- A localised lift and relay is £350 to £900. Rebuilding the base under a failed area is £60 to £110 per square metre, and a full driveway rebuild is £90 to £160 per square metre in 2026.
- Can you just add sand to fill a sunken driveway?
- No. Topping up sand hides the dip for a few weeks. The failure is in the sub-base beneath, so the blocks have to be lifted and the base rebuilt for the repair to hold.
- Is a sinking driveway covered by insurance?
- Rarely. Most buildings policies exclude driveways, paths and patios from subsidence cover unless the main house is affected at the same time. Check your policy wording before assuming.