roof cleaning

Roof Algae Removal

Posted By vorsterroofcleaning

Roof Algae Removal is important in all homes. Moss and algae is normally found on the shady side of properties and often near trees. It is that green or black colour growth on a roof. The roof is normally very slippery and wet where algae is present. Algae are also found on paving under trees in the shade and in a water path. Algae flourish in high rainfall and humid areas. Read more on Cleaning Roofs


It is important to first have a look at plant growth both overhead as well as growth on the ground .This is necessary to not only remove algae but to also to treat the cause of algae growth.

The use of high pressure water stray on tile and asbestos roofs are the most environmental friendly to remove moss and algae. A machine with a 150 to 180 bar pressure is recommended.

Algae and moss can also be removed with a 50% bleach and 50% water mix which are applied. Whilst effective this method can discolour certain roof tiles and is therefore not recommended. This method works well on roofs with shingles.


A proper post inspection is required to ensure that all moss and algae has been removed during the high pressure spraying operation.

Where possible a copper strip needs to be fitted close to the roof peak under the first row of tiles / asbestos. During rain the copper releases material which reduces the chances of algae or moss being formed again.

Coarse salt should also be applied as a follow up procedure 8 months after the roof was cleaned with a high pressure spray. A 3kg bag should cover a 200m2 area. The salt is spread along the top section of the roof which were most affected by algae (shaded and mostly southern side of the roofs in South Africa) Best time to apply salt will be a few days before it rains. This will allow rain to wash the salt off and further neutralize possible algae /moss growth.

Important remember if the Roof Is to be Painted all algae must be removed and treated Read more on Roof Painting

Cleaning a roof and removing algae will improve resale value and save you money long term. For more info on our services read more

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