What's best – pressure washing and/or soft washing?


Pressure washing cleaning tarmac biocide treatment

    What problems do power (aka pressure or jet) wash contractors encounter? 

    • Price competition. The fact that there are few barriers to entry into our industry is a double-edge sword. Unfortunately there are some unscrupulous operators who cut corners by using inferior products and application systems, which enable them to offer what their unwitting customers think is a good deal. 
    • Potential damage from using very high pressure. Not all surfaces will be damaged but many will, including concrete. And even if there is no immediate damage, power washing will inevitably speed up the weathering process and so shorten the life-span of the surface.
    • The rapid re-colonisation of algae, lichen, mould and moss – the cause of 95% of so-called “dirt” on exterior hard surfaces – because power washing alone cannot kill the spores.

    How can Benz Softwash help resolve these problems?

    1. As an active Benz Softwash customer, you can use our website to sell soft washing to your customers, giving you a strong marketing advantage.

    2. Using Bio Cleanze surfaces can be left to "self-cleanse" over time, eliminating the need for high pressure jet washing and expanding the range of cleaning contracts you can take on.

    3. Using Lightning Cleanze or Tornado Cleanze you can offer customers near instant cleaning, which can be a stand-alone treatment or combined with pressure washing (for very severely contaminated surfaces).

    4. You can offer your customers our "Clean & Maintain" softwashing system.

    5. Using our high quality, fully government approved, softwash biocides and time-tested application procedures places your company head and shoulders above your competition.

    6. Using our products and technical information you can reduce or eliminate the need for high pressure jet washing; and when used, enable the pressure to be reduced, safeguarding your customers property and keeping them happy.

     Happy customers become repeat customers

     What surfaces can be damaged by power/pressure washing? 

    • K-rend plaster, or other through-coloured render, will not withstand high-pressure power washing.
    • Surfaces with grouting need great care and we don’t advise power washing them unless absolutely essential.
    • Sandstone. Because it is soft and porous, algae spores breed in the pores. Power washing makes sandstone even more porous and susceptible to algae growth.
    • Tarmac can be damaged by high-pressure power washing.
    • Concrete does not like repeated power washing because it exaggerates weathering and removes some of the top layer of cement each time it is power washed.

    • Brickwork. Similarly to concrete, high pressure power washing removes the protective outer coating, increasing the porosity of the bricks and shortening their life expectancy.
    • Polytunnels, glass greenhouses and conservatory roofs are all too delicate for high-pressure power washing.

    How can Bio Cleanze resolve these problems?

    1. Bio Cleanze can be applied to any surface on which power washing was previously used, to give longer-lasting results without damaging surfaces.

    2. On large surface areas, for example a concrete or tarmac car park, Bio Cleanze offers more effective and economical results for the customer than can pressure washing alone.

    3. Excellent for car parks and industrial estates where instant results may not be valued as much as long-term effectiveness and care of the properties.

    4. Use for maintenance cleans using a low pressure spray application. This will keep surfaces looking permanently clean without the peaks and troughs of power washing. (scroll down to see comparative graphs)

    5. Bio Cleanze is a highly effective product for cleaning greenhouses, conservatory roofs and polytunnels. It is harmless to polythene, pvc, upvc, metals, rubber seals, etc.

    6. Post-treating a power washed surface with Bio Cleanze can increase the longevity of the clean by 2-300% for only minimal extra investment.

    7. The active ingredient in Bio Cleanze is DDAC (Didecel Dimethyl Ammonium Chloride) and is unaffected by hard water.

      Quick tip: Most other biocides use the cheaper but far less effective BAC (Benzalkonium Chloride) that is detrimentally affected by hard water and so gives variable and unreliable results. Our tests show that BAC is not as effective as Bio Cleanze, in both its surfactant qualities and ability to sanitise.

    What do customers dislike about high pressure power washing? 

    • Educated customers know that it can damage the more delicate surfaces of their property and speed up the weathering process.
    • That its results, without post treatment with Bio Cleanze, can only be short-term.
    • The digging out of the cement or sand pointing between paving slabs.
    • The fact that drives, paths and patios quickly re-colonise with algae, lichen, moss and mould – and so rapidly revert to a dirty black appearance.
    • The fact that red and green staining quickly returns to wall render.
    • The fact that roofs quickly build up lichen, algae and moss again.
    • The fact that their property needs cleaning again in only a few months, leading to them feeling dissatisfied and that they have wasted their money.

    Happy customers will refer a contractor to their friends, family and neighbours

    How can using Benz soft wash biocides help create happy customers?

    1. Lower pressure – achieved by using a fan jet for example (and/or turning the pressure down) – can be used on many surfaces, such as timber decking, to get the worst off and then let the post-treatment with Bio Cleanze finish the job.

    2. Low pressure soft washing eliminates the damage and dramatically increased weathering caused by high pressure power washing.

    3. Many surfaces can be treated with Bio Cleanze without power washing first. Because it kills the spores, your customer’s property stays clean longer. This is also the most cost-effective approach to many jobs and is the basis of our "Clean & Maintain" softwash systems.

    4. Benz Lightning Cleanze and/or Tornado Cleanze can take the place of pressure washing, or dramatically reduce the need for it, by cleaning the infestation from a surface, while simultaneously killing many of the surface spores.

      Once rinsed, Bio Cleanze can be applied to kill any remaining, more deeply rooted, spores and provide long-term residual biocide protection against re-colonisation.


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


    What most customers expect

    Softwashing with Bio Cleanze as a stand-alone treatment is highly effective and can be the best practice for customers who are willing to wait for results to show.

    Remember that you’ll need to let your customer know that it will take several weeks for the process to show results – and that the full self-cleansing process can continue for up to a year.

    For softwashing with Bio Cleanze alone to show a similar level of surface cleaning as power or pressure washing – or softwashing with Lightning Cleanze or Tornado Cleanze – several days or even  months should be allowed, depending on the surface and level of colonisation.

    For those willing to wait, the long-term results will be far more effective and much longer-lasting.

    For some colonisations – black lichen for example – the most effective approach can be to combine treatments of Lightning Cleanze, Tornado Cleanze, Bio Cleanze and light pressure / power washing.

    Click here to learn more about removing black spot (black lichen)

    Practically speaking, the majority of customers want to see an immediate cleaning effect. They want to see straight away what they have got for their money.

    So it's often best to first treat with Lightning Cleanze and/or Tornado Cleanze, and then post-treat with Bio Cleanze.

    The exception we've found is soft washing roofs, where treating only with Bio Cleanze is often the best and most effective practice.


    Build a solid base of repeat customers by offering a quick re-treatment with Bio Cleanze every 6-36 months


    This is profitable for the contractor, who will often only have to spray the surfaces with Bio Cleanze every 6-36 months.

    And it's better for the customer because they get a perpetually clean property undamaged by frequent pressure washing. 

    So this is clearly a win-win agreement for everyone concerned.

    Convincing your customers – seeing is believing

    Showing your customers our short and inspiring videos – perhaps on your phone or iPad – is a great way to convince them of the value of employing you to soft wash their property.

    The videos will inspire credibility and confidence in the products you use, encouraging your customers to employ your softwashing services.

    You can also show them these spectacular before and after photos.

    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)


    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 comparative example.

    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 drive remained stable 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 only looks clean until the biofilm builds 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.

    For example, 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 more about combining pressure/power washing with soft washing

    The Benz Softwash range of softwash cleaning products


    Click here to get more practical soft washing how-to tips

    How to find answers to most soft washing questions: Simply enter a relevant "keyword" or short phrase (e.g. keyword for above link = "how to") into our in-site Search Engine (the magnifying glass icon on main menu) 

    You can order Benz softwash chemicals & equipment online or by phone:

    GB (England, Scotland, Wales)

    Phone: 0800 70 74 222 

    Online: www.benzsoftwash.co.uk

    Ireland and other countries

    Phone: 00353 214 622 978

    Online: www.benzsoftwash.com

    Lines open Monday - Friday, 9am – 5pm

    Please note: The above numbers are for orders only (click here for tech support)


    Click here to explore the full range of Benz Softwash cleaning chemicals & equipment

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