How To Clean Your Roof

Cleaning roofs can be a dangerous and difficult task, especially if you have a high pitch roof and are afraid of heights. However, it is a task that must be completed to avoid damage which can lead to leaks and expensive repairs. Algae, moss, and lichen can grow on almost any surface and once these nasty organic growths have developed they can be tough to remove.

To treat these organic growths and stop them from damaging the paint and functionality of your roof it is important to use proper methods in order to ensure longevity.

Not every roof is the same so make sure you are using correct methods for your particular type of roof.

Heres a quick guide on how you can clean your roof. Note, that there is a separate method for Asphalt Shingle Roofs. These methods below are only soft wash methods and do not include any pressure washing.

Asphalt Shingles

If you have asphalt shingles on your roof or have seen them around, you have probably noticed black streaks or in prolonged cases, the roof is completely blackened. This is an algae call ‘Gloeocapsa magma’. This harsh, black algae feeds on a limestone filling in the shingles and can begin to develop anywhere from 3-5 years after installation. Unless you have algae resistant shingles, you should expect this algae to develop and continue to worsen until harsher organic growth such as moss and lichen begin to grow.

This cleaning method suggested below will remove the black stains from the roof on the same. However, moss and lichen grow roots into the shingles and must be allowed to fall away after being killed with this treatment.

Step 1:

Mix concentrated 15% Sodium Hypochlorite with water 1:5 to make 3% Sodium hypochlorite

When cleaning asphalt shingles it is important to note that this roofing system is different to others and requires a unique cleaning method that is recommended by most manufacturers. Using methods that are not approved by manufacturers will result in a warranty void. Most asphalt shingle manufacturers recommend that 3% Sodium Hypochlorite be used as a safe and effective solution.

Protective equipment should be used when handling Sodium Hypochlorite. This includes: gloves, goggles, a respirator and protective clothing.

It is important to note that surfactants should not be used when cleaning asphalt shingle roofs and could result in the warranty being voided.

Step 2:

Cover all Plants that are at risk of over-spray.

Sodium Hypochlorite can be harmful to plants if allowed to directly come in contact so to avoid damage to precious plants, cover them up to be safe rather than sorry.

Step 3:

If on tank water, downpipes or the tank should be disconnected. You should allow at least 2-3 weeks and a few good rain showers before reconnecting.

Step 4: When dealing with heights, make sure you use appropriate safety equipment to minimise the chance of injury.

This means that the ladder you are climbing up onto should be secured properly with multiple anchor points to stop the ladder from falling over or slipping out from underneath you. Even if you are using rope to tie your ladder in, it is still better than nothing.

If you are climbing onto your roof to spray or spraying from the edge of the roof from a ladder, it is wise you use a safety harness.

Step 5:

Spray the 3% Sodium Hypochlorite onto the affected area and allow to sit for 15 minutes.

You should start to see the black algae disappearing before you eyes. Harsher growths such as moss and lichen will turn white as they die. However, as discussed earlier they need to be allowed to fall away on their own to avoid damage to the roof if forced off.

Step 6:

Once you are done spraying, wash down the roof with water thoroughly to wash away most of the chemical. The rain will take care of the rest.

Step 7:

If all the black does not disappear you may be required to repeat the treatment process.

Step 8:

Once you have finished, wash down the surrounding area/ plants and equipment with water.

Decramastic, Iron, Clay, Metal and Concrete.

Step 1:

Acquire a concentrated Benzalkonium Chloride based product and mix with water according to the product's instructions.

Benzalkonium Chloride is great for treating algae, moss, and lichen. Even though it can take a few months to achieve results, it will act to stop regrowths.

Protective equipment should be used when handling Benzalkonium Chloride products. This includes: gloves, goggles, a respirator, and protective clothing.

Step 2:

Cover all Plants that are at risk of over-spray.

Even though Benzalkonium Chloride is not as harsh as Sodium Hypochlorite, it is better to be safe rather sorry.

Step 3:

If on tank water, down pipes or the tank should be disconnected. You should allow at least 3 weeks and a few good rain showers before reconnecting.

Step 4:

When dealing with heights, make sure you use appropriate safety equipment to minimise the chance of injury.

This means that the ladder you are climbing up should be secured properly with multiple anchor points to stop the ladder from falling over or slipping out from underneath you. Even if you are using rope to tie your ladder in, it is still better than nothing.

If you are climbing onto your roof to spray or spraying from the edge of the roof from a ladder, it is wise you use a safety harness.

Step 5:

Spray the target area thoroughly.

Step 6:

Once you have finished, wash down the surrounding areas/ plants and equipment with water.

You are not required to wash your roof with water after spraying.

Step 7:

In 2 months time; inspect your roof to see if the algae, moss and lichen has started to die.

If you think that the volume or concentration was not enough, you may need to reapply at a slightly higher volume or concentration.

A treatment every 1-2 years will ensure you keep those organic growths away.