Choose what you can see. Each answer gives the usual cause, the fix and a guide price. For a firm price, send photos with a tape measure in shot.
Sinking or dipping
Likely cause: A thin or poorly compacted sub-base, a thick sand bed, or water washing material out from a drain.
The fix: Lift the blocks, rebuild the weak base, re-screed and relay the same blocks.
Typical cost: £300–£1,200 inc VAT.
Ruts in the wheel tracks
Likely cause: The layers below have deformed under car loads, usually because the sub-base is too thin.
The fix: Lift and relay the tracks, rebuilding the sub-base to suit cars.
Typical cost: £60–£110 per m² inc VAT.
Loose or rocking blocks
Likely cause: Joint sand has washed or been swept out, or the sand bed is too thick.
The fix: Re-sand and compact; if they still move, lift and re-bed them.
Typical cost: £3–£10 per m² inc VAT.
Blocks spreading at the edges
Likely cause: The edge restraint is missing, broken or was laid on sand instead of concrete.
The fix: Lift the edge, re-set kerbs or a soldier course on a concrete bed and haunch, then close the joints.
Typical cost: £20–£50 per metre inc VAT.
Cracked or broken blocks
Likely cause: Point loads such as skips or jacks, or a block bearing on a stone in the bed.
The fix: Cut out and replace the damaged blocks, correcting the bed beneath.
Typical cost: £200–£650 inc VAT.
Weeds and moss in the joints
Likely cause: Seeds landing in low or debris-filled joints, plus shade and damp.
The fix: Clean, remove weeds, re-sand, and seal if you want to slow regrowth.
Typical cost: £8–£20 per m² inc VAT.
Puddles that never clear
Likely cause: Falls flatter than about 1:80, a sunken area, or water with nowhere to go.
The fix: Re-level the area to proper falls and add a channel or soakaway where needed.
Typical cost: £300–£1,200 inc VAT.
Oil or rust stains
Likely cause: Leaks soaking into porous concrete.
The fix: Specialist cleaning; badly stained blocks swapped for clean ones.
Typical cost: £200–£650 inc VAT.
White bloom on new blocks
Likely cause: Efflorescence: natural salts brought out by moisture. Not a fault.
The fix: Leave it to weather away over a few months; do not seal until it has gone.
