27th August 2021 General

Is Roof Cleaning Safe?

Yes; roof cleaning is safe, if done by trained professionals using the correct equipment and cleaning solutions. Using a high-power pressure washer is not a good idea and is likely to damage roof tiles, remove mortar pointing and force water beneath roof tiles or slates.

Soft washing is the safest and most effective method of cleaning a roof. The process uses a combination of sodium hypochlorite, pure water, and a product such as Green Wash (available from SoftWash Systems), applied at low pressure from a distance of 6 feet away. Soft washing works at a far lower pressure than pressure washing because the low-VOC biodegradable soft washing solution kills and emulsifies organic matter while also breaking down its bond to the roof’s surface. The roof then simply needs a final rinse at low pressure to remove the debris.

A soft washed roof will be free from organic matter (moss, lichen, algae, etc) will stay clean far longer (normally between 4-6 times longer) than if it had been pressure washed because the roof’s surface has effectively been sanitised.

Pressure washing simply rips away the visible organic matter, inevitably leaving plenty behind which may not be visible initially, but with a surprisingly short time, this organic matter would be visible once more, having simply been mowed (and watered!).

Health and Safety

At Purple Rhino, we invest heavily in equipment for working safely at height without ever setting foot on the roof. We take health and safety extremely seriously and underpin this with our comprehensive insurance. It’s vital make sure a roof cleaner’s insurance is adequate. In some cases, if cover is inadequate, liability may be on the home owner’s shoulders.

Soft washing will sometimes reveal cracked tiles. Roof tiles are often cracked BEFORE being soft washed, but being covered in moss made it impossible to see. In this case, isn’t it better to identify and replace cracked tiles sooner rather than later, anyway?

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