Asbestos Roof Steam Cleaning
The normal accepted practice of using a “closed box” pressure washing system has several disadvantages, mainly due to the amount of water that is applied to the roof during the cleaning process.
The fact that the water is applied in all directions, often leads to water ingress in places where the roof has probably never leaked previously.
Another consequence of pressure washing is that the volume of water can easily (and often does) flood the guttering, which can result in asbestos contaminated water cascading down internal and external walls.
If you’ve ever used a patio cleaner attachment on a domestic pressure washer, you’ll understand how adjacent walls are often soiled in the process.
When a commercial grade cleaner is used on a soiled, corrugated roof, the mess from slurry and splashing is considerably worse, though of course, a competent cleaning contractor will clean up afterwards.
Whilst pressure wash lances should never be used, there is a method that can be employed that is even more effective – steam cleaning.
Steam Cleaning Process
The process is far gentler than using water and therefore, no damage is caused to the roof sheets. In fact, when using the steam cleaning nozzle just 2-4 inches from the surface of the roof, it is little more than the effect of rainfall.
What’s more, the water run-off is reduced by around 70% compared to pressure washing, meaning that the gutters are unlikely to become overwhelmed by the volume of water, so this a greener way of cleaning asbestos roofs.
Unlike pressure washing using the closed box system, the roof sheets never become saturated and therefore dry far more quickly – usually in a matter of minutes.
The high temperature of the steam kills moss and removes lichen stains instantly, leaving a surface that is perfect for coating.
Because steam can only be delivered via a lance, it takes longer than when using a closed box cleaner. For a thorough clean, leaving no staining at all on the roof sheets, this can take up to 10 minutes per square metre, per machine.
However, most roof coatings don’t require that level of cleaning and consequently, depending on the roof coating manufacturer’s requirements, the time can be reduced to around 4-5 minutes per square metre or around 100 square metres per 8 hour day.
As a comparison, an equivalent closed box pressure wash system could achieve 200 to 300 square metres per day.
Because the steam method uses a lance to deliver the steam, any debris on the roof is easily dispersed. Consequently, special measures have to be put in place to prevent the accidental contamination of adjoining or adjacent properties and other external areas.
Our system is a two part process that first involves the removal of all moss and vegetation. When this is complete, the roof is steam cleaned in designated areas that are protected by our unique barrier filters placed on the roof to trap any flying debris.
This method is not formally approved (or banned) by the HSE so strict controls measures need to be put in place to ensure that no health and safety breaches occur.
If in doubt about your own project, we will happily engage health & safety consultants, the HSE or any other authority our clients require, prior to commencing an asbestos roof cleaning project.
Remember, that any cleaned asbestos roof will require sealing afterwards to prevent further vegetation growth and deterioration.
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