high pressure roof cleaning on colorbond roof

“Out of sight, out of mind” – it’s too easy to fall into this cleaning and maintenance trap. When faced with an abundance of cleaning and maintenance tasks, it can be easy to prioritise those which are in your face every day. Roof cleaning may not seem that important at first, but what if it could save you a lot of money?

Over time any roof, whether it’s iron, colorbond steel or tile, will become dirty. Algae, lichen, moss, bird poo, or debris from overhanging trees will accumulate. These stains make your property look worn and poorly managed, but there are more reasons to keep your roof clean than aesthetics.

The design and condition of your roof has a significant impact on your energy costs. Energy efficient buildings are designed with roofs which have a high level of solar reflectance, (the amount of solar energy which is reflected by your roof1). Thick surface deposits such as algae absorb, retain the sun’s rays, reducing solar reflectance by 20-55%2 and increasing your cooling expenditure.

Depending on your roof material, the stains on your roof can damage your roofing material, causing permanent damage and lead to holes and leakage. Many newer properties have colorbond roofs which are highly durable and come with long guarantees, however even the manufacturer, Bluescope Steel, recommends cleaning to maintain longevity3.

Properties with older iron roofs can experience corrosion when surface deposits are left to accumulate over time. The images below are from the roof of the Loyola College Chapel in Watsonia, North East Melbourne. The roof had not received any cleaning or maintenance for several decades and required our technician Phil Hudson to repair the holes, clean the roofing iron and repaint the roof (the restored roof is displayed in the second image).

hole in colorbond roof

roof after cleaning was performed

Care must be taken to avoid damage to the roof during cleaning. Damage can be done to seals and flashing from harsh use of high pressure cleaners. A wide angle jet must be used and care taken to avoid excessive direct pressure on seals and flashing to avoid leakage. When cleaning a tile roof, water should be sprayed down the roof, not upwards, to avoid spraying underneath tiles and causing dislodgement.

Harsh chemicals must be avoided to prevent corrosion to the roofing material and spouting, and void any active manufacturer guarantees. Improper cleaning solution choice can also cause environmental damage if it ends up in the sewerage system.

Below is an example of a roof cleaning project performed by Greaham Saville at the Chisholm Institute campus in Cranbourne. Algae, dirt and mould had accumulated over several decades, requiring specialised cleaning solutions to be applied as well as high pressure cleaning.

mouldy roof before cleaning

roof cleanining performed on school roof

The risks involved in cleaning roofs are high, as it involves working at heights, on a slippery, angled surface, using high pressure cleaners which can upset your balance. For these reasons, our technicians wear safety harnesses.

For those who are faced with the accumulation of bird droppings, we recommend that spikes are fitted to the susceptible areas, such as gutters, ledges and chimneys. Below is an example of a solution we fitted to an apartment complex in the Melbourne suburb of Fitzroy.

bird spikes being installed on roof

Tiled roofs can benefit from oxidisation treatment. Oxidisation affects concrete tiles after years of exposure from the sun, causing the surface to erode and a white, powdery substance to appear. The images below display the oxidisation treatment performed on this Gold Coast property by Greg Luckett.

roof tiles before cleaning

roof tiles after cleaning

The Stain Eaters perform roof cleaning throughout Victoria, New South Wales, Queensland and South Australia. For 40+ years’ our stain removal services have been requested by retailers, educational institutions, banks, body corporates and residential properties. As the first stain removal company to achieve international accreditation quality, OH&S, environmental, and risk management, we are prepared to perform dangerous tasks such as these. For your peace of mind, all technicians are covered by a $20 million public liability insurance policy.

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1 University of Melbourne

2 Economic Feasibility of Cleaning Roofs to Maintain their “Solar Reflectance” Ratings

3 Bluescope Steel