How to clean a tarmac driveway (without damaging it)

Tarmac driveways are popular for a reason: it’s strong, weather-resistant, cost-effective, and looks smart with a clean, smooth finish. But it does need the right approach when you’re cleaning it because aggressive pressure washing and harsh chemicals can roughen the surface, pull out the fines (the tiny particles that help bind it), and shorten its lifespan.

Below is a practical, tarmac-specific guide you can follow at home, plus exactly how to tackle green growth and how to remove moss from tarmac driveways safely.

Clean tarmac driveway

Quick answer (if you want the fast version)

1. Sweep thoroughly (stiff broom) to remove grit and debris.

2. Pre-wet the driveway.

3. Wash using warm water + a small amount of mild detergent.

4. Scrub with a soft/medium-bristle brush (not wire).

5. Rinse gently. If using a pressure washer, keep it on a wide fan, low–medium pressure, and at least 20–30cm from the surface.

6. Treat moss/algae with a tarmac-safe biocide and rinse after the recommended dwell time.

7. Repeat light cleaning little-and-often rather than one aggressive deep clean.

Why tarmac needs a different cleaning method

Tarmac is durable, but it’s not as “hard-faced” as some paving types. Overdoing the pressure or using the wrong chemicals can:

• Roughen the surface (making it look patchy/dull)

• Dislodge loose stones or fines

• Expose weak spots that then take on water and dirt faster

• Make future moss/algae growth more likely

If your driveway is older, already brittle, or has areas that look loose/crumbly, it’s worth being extra gentle or getting advice before you start.

What you’ll need to clean a tarmac driveway

• Stiff broom (for dry sweeping)

• Hose with spray nozzle (or watering can)

• Bucket of warm water

• Mild detergent (washing-up liquid is usually enough)

• Soft/medium-bristle brush or deck brush

• Optional: pressure washer (used carefully)

• Optional: tarmac-safe moss/algae treatment (biocide)

Avoid: wire brushes, acid-based patio cleaners, strong solvents/degreasers, and “brick acid.” These can discolour or weaken the binder.

Recently laid tarmac driveway

Step-by-step: how to clean a tarmac driveway

1) Sweep first (don’t skip this)

Start with a thorough sweep to remove grit, leaves, and loose dirt. This matters because grit acts like sandpaper when you scrub, and wet leaves can stain.

Tip: Pay attention to edges where debris collects—especially if you’ve got block borders (common on tarmac drives).

2) Pre-wet the surface

Give the driveway a gentle soak. Pre-wetting stops detergent drying too fast and helps lift surface dirt instead of grinding it in.

3) Wash with mild detergent

Mix warm water with a small amount of mild detergent. Apply it in sections (so it doesn’t dry out) and let it sit for a few minutes.

4) Scrub gently

Use a soft/medium brush to agitate the grime. You’re aiming to lift dirt, not “sand” the surface.

Technique that works well:

• Brush in overlapping passes

• Rinse each section as you go

• Don’t scrub a dry area—always keep it damp

5) Rinse thoroughly

Rinse until the water runs clear. If suds remain, they’ll attract dust and your driveway will look dirty again faster.

Using a pressure washer on tarmac (do it the safe way)

You can use a pressure washer on tarmac, but only if you’re careful.

Pressure washing rules for tarmac:

• Use a wide fan nozzle, not a pencil jet

• Start on low pressure and increase only if needed

• Keep the lance moving constantly

• Keep at least 20–30cm distance

• Avoid blasting cracks, edges, and patched areas

• Never linger in one spot

If the surface starts to look “furry,” pitted, or you see stones lifting—stop. That’s a sign you’re being too aggressive.

Tarmac driveway with block border

How to remove moss from tarmac driveways

Moss and algae thrive in damp, shaded areas—especially in the West Midlands where surfaces can stay wet for long periods. The goal is to kill the growth at the roots and prevent quick regrowth, without damaging the tarmac.

Step 1) Remove loose growth

On a dry day, brush off as much moss as possible with a stiff broom. This exposes what’s underneath so treatments work better.

Step 2) Apply a tarmac-safe biocide

Choose an outdoor moss/algae killer that’s suitable for tarmac/asphalt (check the label). Apply as directed—usually with a watering can or sprayer.

Important: More product doesn’t mean better results. Over-application can leave residue and may affect nearby planting.

Step 3) Let it work (don’t rush the rinse)

Most treatments need time to break down growth. Follow the dwell time on the product. Some products work over days and are designed to be left to weather away.

Step 4) Rinse gently and brush again if needed

Once the moss has browned off, brush again and rinse. If you pressure wash at this stage, keep it low pressure and wide fan—think “rinse” not “blast.”

Step 5) Prevent it coming back

• Trim overhanging plants to increase light and airflow

• Keep the driveway swept (leaves feed moss)

• Consider a periodic biocide treatment in shady areas (as needed)

Common tarmac stains and what to do about them

Oil spots (cars, bins, etc.)

1. Blot fresh spills immediately (don’t rub)

2. Use warm water + mild detergent and a soft brush

3. For stubborn spots, use a tarmac-safe degreaser (label must say it’s suitable) and rinse well

Avoid strong solvents—they can soften the binder and cause permanent marks.

Tyre marks

Often lift with warm soapy water and brushing. If not, a gentle rinse with a low-pressure washer can help.

Rust stains

Treat carefully: many “rust removers” are acidic. If you’re unsure it’s suitable for tarmac, don’t use it. Test any cleaner in a discreet corner first.

Tarmac driveway with block paving enterance and border

How often should you clean a tarmac driveway?

A simple routine keeps tarmac looking good with minimal effort:

• Weekly/fortnightly: quick sweep (especially in autumn/winter)

• Every 2–3 months: mild wash + rinse

• As needed: moss treatment in shaded areas

A “little and often” approach is usually better than one heavy-handed clean per year.

When it’s better to refresh (not just clean)

Sometimes cleaning won’t fix the underlying issue. You may be better off with a refresh or repair if you notice:

• Cracks spreading or widening

• Loose, crumbling patches

• Significant dips/ponding after rain

• A heavily faded, patchy finish that never looks clean for long

Drive Tech UK provides new tarmac driveways and can also help you refresh existing surfaces—aiming for a long-lasting, low-maintenance result and clear quotes that break down costs.

FAQs

Can I use bleach on a tarmac driveway?

It’s not recommended. Bleach can discolour surfaces and damage nearby plants. A tarmac-safe biocide is a better option for organic growth.

What’s the best thing to clean tarmac with?

Warm water, a mild detergent, and a soft/medium-bristle brush covers most dirt. For moss/algae, use a tarmac-safe biocide.

Why does my tarmac look patchy after cleaning?

Patchiness often comes from uneven pressure washing, detergent residue, or cleaning a surface that’s already oxidised/worn. Gentle cleaning and thorough rinsing help—if it persists, the surface may need professional advice.