How to soft wash tarmac, including driveways and car parks?

Tarmac surfaces attract algae, moss, mould and lichen, which require periodic treatment through soft washing.

In most cases, Benz Bio Cleanze is the most effective option for treating tarmac, allowing the surface to gradually clean over time.

How to treat tarmac with Bio Cleanze

Bio Cleanze can be applied directly to tarmac. Where there is heavy moss, light scraping or a gentle pressure wash beforehand will improve results and reduce product use.

If growth remains embedded within the surface, brushing in the application can help ensure full coverage. Where growth is more superficial, spraying alone is usually sufficient.

Following treatment, moss will begin to brown and break down, gradually clearing through natural weathering over the following weeks and months.

Quick tip: A follow-up treatment at around 6 months will help deal with any remaining spores and extend the clean.

Application and dilution

Typical dilution for Bio Cleanze on tarmac is 25:1 to 50:1, depending on conditions and level of growth.

The correct dilution depends on:

• Temperature (colder conditions may require stronger mixes)
• Severity of growth
• How long the surface has been untreated

If children or pets will use the area, apply at a maximum of 50:1 and keep the surface clear until fully dry.

After this, increase concentrations until you have satisfactory cleaning results. Always test small areas first.

Quick tip: Tarmac can be surprisingly absorbent due to its structure, so expect higher product usage compared to smoother surfaces like concrete.

Clean and maintain approach

A second treatment after 6 months can significantly extend results. Ongoing maintenance at 12–24 month intervals helps keep surfaces consistently clean.

This approach allows customers to maintain a clean surface year-round, rather than waiting for heavy contamination to return.

Learn more about the Clean & Maintain approach

Using Lightning Cleanze on tarmac

Benz Lightning Cleanze can be used where fast results are required.

It will deliver near-instant cleaning, but can leave behind a white residue as growth breaks down, which may require rinsing.

For this reason, it is typically used where appearance is needed quickly, such as pre-sale cleaning.

Important: Always control run-off and avoid directing rinse water into sensitive areas such as lawns, planting or surface drains.

Will soft washing change the colour of tarmac?

Bio Cleanze will clean the surface, which can make it appear lighter simply because contamination has been removed. In most cases, the original colour remains unchanged.

Lightning Cleanze, however, can cause actual lightening of the surface, particularly at stronger dilutions.

For this reason, we recommend working at around 10:1 and always carrying out a test patch before full application.

Quick tips:

• Treat the entire area for a consistent finish
• Remove heavy moss before treatment to improve efficiency
• Use either Bio Cleanze or Lightning Cleanze — not both on the same surface

We wish you all the best with your soft washing business,
Team Benz

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