Tarmac Driveway Cleaning: A Practical Guide

Why tarmac drives go green and grubby

Tarmac is slightly porous and its surface texture holds fine soil, leaf fragments and tyre dust. In shaded spots that layer stays damp, and algae and moss move in. The edges beside lawns and borders are usually worst, because soil washes onto them every time it rains.

Older tarmac also develops hairline cracks as the binder ages and hardens in the sun. Each crack becomes a narrow seed bed, and moss or weeds rooted in it slowly widen the gap.

The risk of too much pressure

A narrow, high-pressure jet held close to tarmac can strip the fine surface material and leave the larger stones exposed. Once chippings start to work loose, the drive looks rougher than before and wears faster under tyres. Warm weather makes the binder softer and more vulnerable.

For that reason, cleaning tarmac is about controlled water, the right tool for each area and patience with stubborn growth rather than simply turning the pressure up.

How we approach a tarmac drive

We start by looking at the whole surface: loose patches, cracks, sunken areas, edging and drainage. Moss and weeds are lifted out of cracks and edges by hand or with suitable tools before the main clean. The surface is then washed with a method chosen for its condition, keeping pressure moderate and the lance at a sensible distance.

Where algae is the main problem, a treatment may be suggested to deal with what washing leaves behind. Whether it is suitable is confirmed when we see the drive, along with what will happen to run-off near plants and drains.

Stains that behave differently

Leaf tannins from oak and other trees can leave brown shadows on a light grey drive. Tyre marks build up where cars turn on the spot. Oil and fuel drips soften bitumen itself, so they need extra care: aggressive solvents can make the softened patch worse. Our guide to driveway oil stains explains why.

Some marks fade a lot with cleaning; others become lighter but stay visible. We tell you which is which before starting so the result matches what you expect.

What cleaning cannot do

Cleaning will not re-bind loose stone, fill potholes, level dips or replace faded colour. If the drive has reached the point where large areas are crumbling, the honest answer may be repair or resurfacing by a surfacing contractor rather than a clean.

On a sound drive, though, removing growth and grime can make a striking difference, and clearing the cracks slows further damage from roots.

Keeping tarmac looking better for longer

Sweep the edges regularly, especially in autumn when leaves sit and rot. Keep gutters and downpipes working so roof water is not spilling onto one patch of the drive. Trim overhanging hedges to let light and air reach shaded corners.

Parking in exactly the same place every day concentrates tyre wear and drips; moving the car slightly now and then spreads the load.

Edges, kerbs and drainage channels

Tarmac drives are usually finished with a kerb or edging course of blocks, and those edging joints are where weeds take hold first. A clean that ignores the edging leaves the drive looking unfinished, so the border is cleared along with the main surface.

Channel drains and gullies at the foot of a sloping drive collect the dirt that washes off. We check they are running before and after the clean, because a blocked channel sends water straight back across the surface the next time it rains.

Getting a tarmac driveway quote

Send a few photographs of the whole drive and any problem areas, and tell us roughly how long it is and whether it slopes towards the house or road. Our driveway cleaning service page explains how a visit works, and quotes are free.