Tarmac & Asphalt Cleaning

Tarmac is the surface people are most confident about and most often wrong about. It's black, it's tough, it carries lorries — so surely it can take a proper blast. In fact it's one of the few surfaces where our usual escalation is backwards: less heat and less pressure, not more.

The reason is what tarmac actually is. Stone aggregate held together by bitumen, which is a petroleum product. It softens with heat and dissolves in solvent. Both of the tools we'd normally reach for on a stubborn stain are precisely the two things that damage it.

Why heat and solvent are the enemy

Turn a steam lance or a hot pressure washer on tarmac and the binder softens. Add the mechanical force of the jet and it lifts, taking loose aggregate with it and leaving a scoured patch that continues to ravel under traffic. On a warm day in an exposed car park, the surface may already be soft before we start.

Solvent is worse, and this catches people out with graffiti. Standard graffiti removers are designed to dissolve paint binders — and bitumen is a binder. Apply a strong remover to a tag sprayed on a car park surface and you'll often remove the tag and a shallow layer of the tarmac with it, leaving a bleached, pitted patch that looks worse than the graffiti.

So on tarmac we work cold or barely warm, at moderate pressure, and we test any chemical on a discreet corner before it goes anywhere visible.

What we can achieve

Realistic expectations matter more here than on any other surface, so it's worth separating what cleaning fixes from what it can't.

Cleaning removes what's sitting on the surface: moss and algae along the edges and in shaded strips, silt and leaf mulch, general grime, tyre rubber, litter residue and surface oil. That work is straightforward and makes a real difference, particularly on car parks where the green edges and channels are what read as neglect.

What cleaning can't do is restore colour. Tarmac fades from black to grey because UV oxidises the bitumen at the surface — the colour loss is a chemical change in the material, not a layer of dirt. A clean grey car park is still grey. If a client wants black, that's a surface dressing or a resurfacing job, and we'd rather say so at quote stage than have them expect a transformation the method can't deliver.

• Moss, algae and silt in channels, edges and shaded areas — very effective
• Surface oil and traffic film — good results with a degreaser and a cold rinse
• Gum and litter residue — effective with care on temperature
• Line marking — cleans up well, and we'll flag where relining would finish the job
• Faded grey colour — cleaning will not fix this, it needs resurfacing

Playgrounds and school surfaces

A large share of our tarmac work is on school sites — playgrounds, MUGAs, ball courts and the paths between buildings. These surfaces go green quickly because they're often shaded by buildings or trees and get little traffic in the holidays, and green tarmac in wet weather is genuinely slippery, so it's a safety issue rather than just an appearance one.

Because these are children's surfaces we normally work chemical-free — cold water at moderate pressure with mechanical agitation, no products left on a surface that children will be sitting on. Where a biocide is needed for heavy growth we'll agree the product and the re-entry period with the school in writing beforehand. Our playground cleaning page covers how we handle school sites.

Oil on tarmac

Oil on a tarmac car park is a particular problem because bitumen and engine oil are chemically related. The oil doesn't just sit on the surface — it softens and penetrates the binder, which is why long-standing oil patches on tarmac often feel slightly soft underfoot and why the tarmac around a regular parking spot can visibly deteriorate.

We can lift surface oil with a degreaser and a cold rinse, and that makes a significant visual difference. What we can't do is undo the damage where oil has broken the binder down — that patch will keep its mark and will continue to deteriorate. Where a bay has reached that point, a localised repair is the real answer, and it's worth knowing before spending money on repeated cleaning.

Timing and drainage

Tarmac work is more weather-dependent than most. On a hot day an exposed car park surface can be well above air temperature and already soft, so we schedule that work for early morning or an overcast day rather than a July afternoon. In winter we avoid leaving standing water on a surface that's about to freeze.

Drainage matters too. Tarmac car parks usually drain to gullies that discharge to surface water, and the run-off from cleaning carries oil and rubber. We check the drainage arrangement and use containment or recovery where the site needs it — the same approach we take on concrete decks.