Asbestos Roof Steam Cleaning

asbestos roof steam cleaningAs an alternative to the Closed Box pressure cleaning system, it may be preferable to use steam cleaning, which uses 150 degree, super-heated steam, rather than water pressure to remove moss and lichen staining.

Please note that this method of asbestos roof cleaning is not approved by the HSE for use in England and Wales. That said, if the proper precautions are taken, there is no reason why it should not be used.

As with all cleaning methods, a complete and comprehensive methodology must be employed to ensure that the safest practices are employed.

Our unrivalled expertise in this area has led to us developing a comprehensive system for asbestos roof steam cleaning and through our dedicated asbestos roof cleaning web site, we now offer a training course and all the equipment necessary to fulfil asbestos roof cleaning works safely and efficiently.

The equipment required for asbestos roof steam cleaning on an industrial sized roof doesn’t come cheap, with each machine costing somewhere in the region of £6,000.

Some manufacturers will hire out their steam cleaning machines, which for companies that only make limited use of them, is a preferred option.

The time it takes to clean a roof using steam is longer than using the closed box method. This is because a single steam nozzle is used, rather than a swirling jet of water.

Steam is delivered to the nozzle via a 30m hose at a temperature of up to 150 degrees at a pressure of around 70 bar at the nozzle.

Unlike pressure cleaning, the stress placed on the asbestos roof panels is little more than rainfall, meaning that even fragile areas can be cleaned with confidence and without risk of damaging fragile roof sheets.

Asbestos roof steam cleaning is extremely environmentally friendly, since no chemicals are used and the steam evaporates, meaning that water run-off is reduced by around 60% with the roof taking far less time to dry than when using water.

The depth of cleaning required will depend upon the coating that is being applied to the roof afterwards.

Some coatings require less aggressive cleaning than certain coatings and so time can be saved by not cleaning too thoroughly. However, if a spotless clean is required for a particular coating, then steam cleaning will achieve the result required.

In short, asbestos roof steam cleaning is preferable in certain cases, though it takes longer to complete than some other methods. To speed up the cleaning process, larger moss balls are manually removed prior to steam cleaning.


Regardless of the cleaning method employed, all waste water collected from the roof needs to be filtered, because any moss is likely to contain asbestos fibres and whilst these are relatively harmless outdoors, they should not be allowed to enter the water system and must be disposed of as contaminated waste afterwards.

Because steam cleaning kills all moss and algae spores, regrowth is likely to be slower than when using dry scraping or pressure cleaning methods.

However, the roof surface will still be prone to moss and lichen, especially in areas close to trees and for this reason, a cleaned asbestos roof must be sealed shortly afterwards.

We recommend Asbestoseal for sealing an asbestos roof after steam cleaning as it’s the only product on the market that was specifically developed for use on asbestos cement roofs, is solvent free and is made in the UK.

Asbestoseal is the only roof coating that has BBA Approval for use on asbestos cement roofs. 

Additionally, it comes with a 20 year Latent Defects Insurance Guarantee as standard on full roof installations. This can be offered because Asbestoseal is only available via the manufacturer’s approved installer network.

For expert advice on asbestos roof cleaning and coatings, please call us on 0121 709 5352 and we’ll be pleased to talk you through the options depending on your circumstances.