Why It’s Important to Roof Wash Wellington

While you may put a lot of effort into the interior of your house and take good care of your lawn, it is equally important to focus on the exterior. Keeping your property clean will not only increase its curb appeal, but it will also help prevent the build-up of moss and other issues.


The moss that grows on roofs and other surfaces is not just unsightly – it can cause structural damage. Left untreated it causes shingles to rot, pull away from the wood rafters or degrade concrete & clay tiles. It can also clog gutters and lead to water damage. It’s a great breeding ground for mould spores, and is also a fire hazard.

A moss spray (Benzylamonium Chloride Solution) saturates the surface and kills moss, mould and lichen. Once killed the growth then dries and eventually breaks down. Rain then washes it away over time. PROS – fast and effective, chemical free, no access needed, cleans bird droppings and other debris from the surface, dries faster than high pressure washing.

A combination of an initial pressure clean and annual moss spray treatments is the best way to keep your Roof Moss Free. A Roof that is moss free lasts longer than one that is not. It is recommended that you clean your roof in year 1, then the following year have an annual moss spray treatment and then repeat as required.


The black discoloration and streaks you see on roofs in coastal or humid areas are actually algae, not mold or mildew. It thrives where moisture lingers on surface, and New Zealand’s climate creates the perfect conditions for this unsightly invader.

Algae spores are carried by wind or animals and can quickly spread from one rooftop to the next. Like moss, algae can cause permanent damage to asphalt shingles and degrade the protective sealant coating on modern concrete tile roofs.

Algae can also discolor and damage exterior surfaces around your home, causing concrete, timber and paving materials to darken or crack. This can also make pathways and driveways slippery, contributing to ACC injury accidents. Regular inspections and cleaning can prevent these unsightly growths from developing. Keeping surfaces dry by ensuring proper drainage and trimming overhanging trees can help, as can the use of roof and exterior surface coatings that deter mould, algae, and lichen growth.


Your home is your biggest investment and the roof is one of its most vulnerable areas. Dirty roofs can mask cracks in tiles or leaks that need fixing. Routine cleaning helps to safeguard the longevity of your roofing materials and keeps a steadfast barrier against invading water damage.

Our coastal and humid weather makes conditions perfect for the growth of moss and algae. The black staining and streaks seen on many homes is actually algae, not mildew or mold.

The best solution to eliminating moss, algae and dirt is to have your roof steam cleaned. A professional using a high powered jet washing machine with adjustable water flow pressures can wash your Wellington roof without causing any damage to the tiles. Once the moss and other accumulations have been removed they will use a biocide treatment to stop re-growth.


Molds are fungi that thrive in moist conditions. They spread from tiny spores that float in the air and land on damp spots or surfaces. Once they grow on these surfaces, they start digesting them and releasing toxic substances, which can be harmful to humans.

There are thousands of mold species, with black mold being particularly dangerous. It may cause a variety of health issues including skin irritation, respiratory problems and headaches. It can also trigger allergic reactions.

There are some cleaning solutions that can kill visible mold, such as ammonia and bleach solution. However, these are dangerous to use and may not be fully effective on all materials. The only way to eradicate mold completely is to remove the moisture source. This could mean fixing a leaky roof, sealing windows and addressing drainage issues. It also means keeping the home and building dry to prevent further damage.

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