Best practices for soft wash cleaning sandstone

September 03, 2019

Best practices for soft wash cleaning sandstone

How can you use Benz powerful Tornado Cleanze thick gel cleaning product for soft washing sandstone?

Soft washing sandstone with Tornado Cleanze

1. Apply liberally by brush and leave Tornado Cleanze for 15-60 minutes to activate on porous surfaces, such as sandstone.

Quick tip: On non-porous surfaces such as industrial cladding you will see results in less than 10 minutes, even when the product is greatly diluted. Experience will inform you how to approach the various materials and local conditions, and what strength of Tornado Cleanze to use.

2. Use a medium soft brush to brush-in Tornado Cleanze. A 9 inch brush can be useful for awkward areas. Sometimes, for heavy black lichen for example, you may find a slightly stiffer brush useful.

3. Do not use high pressure washing on sandstone. This will damage the surface layer of the stone, and if live growths are present will rip out the roots, further damaging the soft stone.

4. Give the sandstone a light, low pressure, jet wash prior to treating with Tornado Cleanze. This is to remove loose matter from the surface, remove some of the more shallow-rooted growths, and will remove some of the skin from the remaining growths. Pre-cleaning sandstone like this will allow Tornado Cleanze to work faster.

Quick tips:

  • Set your jet washer to low pressure if you have a variable control, and/or fit with a fan jet, and hold well back from the surface.

  • We've found that a light jet wash is more effective than sweeping the surface clean of loose matter, or using a blower.

5. Giving a biocidal treatment with Benz Lightning Cleanze biocide, to kill the growths and sanitise the sandstone prior to cleaning with Tornado Cleanze, can produce the most effective results. This also serves to pre-wet the surface, making the application of Tornado Cleanze easier, quicker and more effective.

6. Sandstone can be slower to come clean than hard stone like granite. This is why some "less than ethical" contractors employ high pressure washing, and dangerously high concentrations of sodium hypochlorite, to quickly produce a "Wow!" result that impresses customers who know no better.

In their pursuit of a fast buck they ignore the damage they do to their customer's property and the damage that long-term chlorine exposure does to their, and their employees, lungs. They rarely get repeat business ...

7. Complete the treatment of sandstone with an application of Benz Bio Cleanze (Max 50:1 if children & animals will walk on it soon after treatment, otherwise it can be applied at up to 20:1 dilution).

Determine the strength at which to use Bio Cleanze by assessing factors such as a) how long since the sandstone was last cleaned b) how bad the colonisation of the sandstone is c) the local environment in which the sandstone lives.

Quick tips:

1) Bio Cleanze continues to deep clean porous surfaces such as sandstone up to a year following treatment.

2) Bio Cleanze imparts a degree of residual protection against re-colonisation that neither jet washing nor any sodium hypochlorite product/mix can offer.


Click here to get more practical soft washing how-to tips on how to use Tornado Cleanze

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

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

GB (England, Scotland, Wales)

Phone: 0800 70 74 222 


Ireland and other countries

Phone: 00353 214 622 978


Lines open Monday - Friday, 9am – 5pm

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

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

Ben, Leo, Fiona, Stevie & Anthony

PS: After completing the first soft wash treatment, put your customer on a "Clean & Maintain" ongoing maintenance programme. Your customers will enjoy a permanently clean property and you will enjoy a steady stream of repeat business.

This is clearly a win-win arrangement for both customer and contractor.


Click here to explore the extensive range of Benz softwash cleaning chemicals & equipment

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

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