Do you know the best time of year to soft wash concrete paths, drives & patios?

January 05, 2022 2 Comments

Do you know the best time of year to softwash concrete paths & patios?

Benz clean & maintain softwash treatment systems are fantastic for cleaning and then keeping the treated concrete paths, drives and patios permanently clean all year. 

Surfaces treated by soft washing, or post-treated after power washing, will stay clean far longer than is possible through other cleaning methods, because soft washing kills the algae spores that power washing alone cannot kill. 

Quick tip: Concrete exposed to high pressure jetting can easily have the surface layer removed ("Whirl-away" machines can do this as well). This shows up as faster than normal weathering.

To avoid damaging your customer's concrete, set your power washer to relatively low pressure, use a fan jet, and hold the head some distance away from the surface.

Dealing with algae "flare-up" on concrete paths, drives & patios

One of the nuances of soft washing when maintaining previously cleaned horizontal surfaces, concrete paths and patios in particular, and keeping them clean all year round,  is knowing how to deal with the occasional flare up of green algae.

A flare-up of green algae can look seriously dramatic, so your customers need to have the situation explained to them in advance, so they know what to expect and don't start thinking that you've done a bad job.

In the video below Ben shows a couple of examples, outlines the reasons why algae flare-up happens, and explains how to best manage your customers expectations.



Problems that can arise when soft washing horizontal surfaces

    1. Green algae re-appears only a few months after treating a concrete horizontal surface such as a path or patio.

    2. Dilution strength is limited to 50:1 on surfaces used by children and animals (compared to up to 20:1 that is possible on roofs and walls), which reduces the time that residual protection against re-colonisation can last.

    3. Because of frequent dilution by rain, and therefore the reduced ability of the surface to drain and dry, residual protection against re-colonisation will be relatively limited compared to a roof or wall that is able to drain and dry quickly.

Solutions to the above problems

  1. Tell your customer in advance (when quoting) that there may be a flare-up of green algae after only a few months, often in November, but this will only be only light.

  2. Tell your customer that you can return to treat the flare-up with Benz Bio Cleanze for a nominal fee, or build this into your original quote and position as a free re-treatment.

  3. Offer your customer a "Clean & Maintain" ongoing programme to keep their property permanently clean.


We hope this information is helpful and sincerely wish you great success in your soft washing business,

Ben, Leo, Fiona, Stevie & Anthony


Click here to explore all Benz softwash cleaning chemicals & equipment

Benz Softwash Bio Cleanze DDAC biocide & Benz Softwash Lightning Cleanze SH sodium hypochlorite biocide

2 Responses


January 25, 2022

Hi Geraldine, we cannot comment on the work of an independent contractor because there are so many variables including the type of softwash product used, the dilution strength, the local environment, the time allowed for activation, and the material the roof is made from. When we treat a roof we would expect the majority of black mould to be gone in a few months, as your contractor explained. If it has not your recourse is to contact the contractor so they can visit and take the appropriate action.

Geraldine O Beirne
Geraldine O Beirne

January 25, 2022


I got my roof cleaned last spring. The black mould never really disappeared. I expected that it would take a few months as explained by the contractor that I hired but how long more before natural weathering before my roof will be clean?

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