How to safely soft wash asbestos roof slates, tiles & sheeting

September 15, 2021

How to safely soft wash asbestos roof slates, tiles & sheeting

Many soft wash contractors can be unsure of the safest way to soft wash asbestos roofs. So in this post we lay out the best practices we've learned from our experience of running a soft washing business since 2013. 

The procedure for soft washing asbestos

First spray the asbestos with copious amounts of water. And repeat water spraying frequently during the scraping process to ensure the asbestos does not dry out.

The water will lay the fibres, preventing them from lifting into the air where they can be taken into your lungs. 

How dangerous is it to soft wash asbestos?

Although the danger when working with asbestos in the open air is relatively small compared to working with asbestos in a confined space, the safest route is of course to wear suitable, asbestos fibre approved, breathing apparatus.

The asbestos can then be treated with Bio Cleanze and/or Lightning Cleanze. Which to use depends on the type of roof and the expectations of your customer.

Mostly we treat roofs with Bio Cleanze only but on the illustrated garage roof Lightning Cleanze turned out to be the most effective treatment, not least because the customer wanted a rapid result.

The photo at the top of this post shows the completed asbestos sheeted garage roof that we treated with Lightning Cleanze. The photo below shows three stages of the work in progress, so you can see what we were faced with and how the job progressed.

How to safely soft wash asbestos roof slates, tiles & asbestos sheeting



Soft washing asbestos roof slates and tiles

It's always good working practice to check the material of the slates you intend treating because some older man-made artificial slates (often called "composite" slates) include asbestos.The asbestos is included in the fibre cement the slates are made from.

Newer man-made slates are fine but anything pre 1970 should be checked for asbestos. A sample can be sent away to a lab to be tested.

We check every roof for asbestos before scraping it, even though the danger is very slight given the open-air conditions, and that the slates are wet all the time when we are scraping them.

Which insurance companies cover the risk of soft washing asbestos?

Modern artificial slates such as Tegral are not made from asbestos-containing material and so are easy and safe to treat.

It's best not to work with old asbestos slates if feel unsure of what you are doing and/or you cannot get insurance.

The best insurance company for soft washing that we know of at the moment is Hiscox. Contact info below:




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

Ben, Leo, Fiona, Stevie & Anthony


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

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