What's Best – Pressure Washing and/or Softwashing?


Softwashing England biocide DDAC 50

“I am truly impressed by just how clean the pavement slabs are in my drive. I got it cleaned last July and it is now long passed Easter – and following the winter weather it is still unbelievably clean.

"The products used to clean the drive are second to none, so gentle, non-abrasive but remarkably effective. Previously I had my drive power-washed and found that while it was certainly clean afterwards, it did not last through the winter. The whole process was quite harsh and even moved some of the paving slabs. I cannot recommend this product – Benz Biocidal Wash – highly enough."

Muireann Curtin, Cork, Ireland (the owner of the test driveway)

    Click here to learn how to combine pressure washing and soft washing


      We created the graphs you see on this page using the following process

      The test project: We chose a Cobblelock drive adjoining a concrete footpath as an example of a typlcal job that softwashing contractors will be familiar with. We first pressure, or power, washed it to remove the weeds and heavy soiling. This gave our customer an immediately clean drive. Then we followed up with a treatment of Benz Bio Cleanze.

      Cobblelock driveway power washed and treated with BENZ Biocidal Wash


      Logging the data: We logged test data once every six weeks (these are the figures on the tabulated data sheet).

      We judged the level of cleanliness by direct observation and gave it marks out of 100 to create a percentage. We used a neighbour's drive, which they pressure washed (aka power or jet washed) at the same time but without post-treating with Bio Cleanze, as a control.

      You can see this in the photo below.

      Cobblelock driveway power washed only without treating with biocide


      Driveway power washed and treated with BENZ Biocidal Wash and a driveway power washed only

      The tabulated data from which the graphs are derived

      Tabulated data from which the graphs are derived


      The "Typical 2-year Cleaning Cycle by Power Washing Alone" graph

      This shows how power/pressure/jet washing produces an apparently clean surface but leaves behind the spores – so can never score 100%.

      This means the surface immediately starts becoming dirty again in places. Nothing major, and may be weather dependent, but this explains the small dip in the graph line.

      The overall cleanliness of the power/pressure/jet washed drive stayed steady for a while. Then, during a change in season, the surface rapidly began looking dirty again as micro organisms re-colonised the surface.

      The graph is relatively smooth from this point as the colonisation is rapid and consistent.

      Power washing without post-treating with BENZ Biocidal Wash

      The "Typical 2-year Cleaning Cycle by Power Washing and Post-treating" graph

      This shows how power washing gives an instant clean. Then Bio Cleanze continues the cleaning process for several months until it is 100% clean.

      As the deep-rooted spores are killed off, only a microscopic biofilm is able to form from the new spores landing on the surface. The biofilm cannot be seen with the human eye. This means the surface looks clean for many months until the biofilm begins to build up again.

      We ended the study after 27 months because the results clearly demonstrate the advantage of post-treating with Bio Cleanze following power/pressure/jet washing.

      We would expect the graph line to point more steeply downward from this point as re-colonisation becomes increasingly rapid.

      Power washing followed by post-treatment with BENZ Biocidal Wash

      The "2-year Cleaning Cycle Following Bio Cleanze Treatment Alone" graph

      This was a different job to the above graphs but is typical of most horizontal surfaces.

      The staggered line on the cleaning cycle shows how surfaces can clean at varying speeds as the seasons change. Localised variations in temperature and prevailing weather can also affect the cleaning cycle.

      Temperature and prevailing weather can affect how a surface looks at any particular point in time, which explains the erratic curve of the graph.

      This graph line looks wavy as colonisation is inconsistent, which could have been caused by local conditions or by the regrowth of a species contained in heavy soiling (in the cracks in concrete or cobblelock for example) which was not removed before treatment.

      This would have been achieved had the surface been pressure washed prior to treating with Bio Cleanze.

      On large areas of concrete, in good condition with little organic growth nearby, the graph would be much smoother.

      Click here to learn when to pressure wash – and when not to pressure wash


      2-Year Cleaning Cycle Following Treatment with BENZ Biocidal Wash without power washing

      Click here to learn how to combine pressure washing and softwashing


      Learn more about softwashing via Benz Trade Tips softwashing how-to posts

      The Benz Softwash range of softwash cleaning products


      Explore the full range of Benz popular softwash cleaning products

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