How to Clean a Tarmac Driveway (Without Damaging It)
4 July 2026 · 6 min read
Tarmac reacts badly to petrol solvents and hot pressure washing. Here's the safe way to remove moss, oil and grime from a tarmac driveway in London.
Tarmac (asphalt) is the most misunderstood driveway surface. It's tougher than block paving in some ways — no joints to weed — but the bitumen binder is soft, so wrong cleaning ruins it fast.
The two rules of cleaning tarmac
- No solvents. Petrol, diesel, WD-40, white spirit and paint thinner all dissolve the binder.
- No hot pressure washing. Above ~60°C the bitumen softens and pits.
Routine cleaning
Sweep weekly to prevent grit acting as sandpaper under car tyres. Rinse with a hose every month or two, especially in autumn when leaves stain the surface.
Moss and algae
Very common on shaded London tarmac. Use a moss killer, leave 24 hours, then brush off with a stiff bristle broom and rinse. Avoid pressure washing dead moss — it drives spores into the surface.
Oil and diesel stains
Cover fresh spills with cat litter or sawdust for 30 minutes, then sweep. Follow with warm water and washing-up liquid, scrubbed in with a soft brush. Old, dry stains rarely come out fully — a top dressing (£3–£6 per m²) is the usual fix.
When to use a pressure washer
Only cold water, under 100 bar, from 40 cm away, moving constantly. A stationary nozzle blasts a hole in tarmac within seconds.
When to call a professional
If the surface is going grey, crumbling at the edges or full of hairline cracks, cleaning won't fix it — you need a rejuvenator or top dressing. Most London driveway cleaners offer this alongside cleaning.