Moss, mould, lichen and other organic growth can gradually build up on roof surfaces, particularly in damp and shaded areas. Apart from affecting the appearance of your property, heavy organic growth can hold moisture against the roof surface and make the roof look neglected.
For many roofs, a professional roof treatment can be an effective alternative to high-pressure cleaning.
What Is Roof Treatment?
Roof treatment involves applying a suitable treatment solution to the roof surface to target moss, mould, lichen and other organic growth.
Rather than relying on high pressure to physically remove everything from the roof, the treatment works over time to break down the organic growth. Rain and weather conditions then help wash away the dead material naturally.
This makes roof treatment particularly useful for roof types and structures where pressure washing may not be appropriate.
Why Doesn’t Every Roof Need to Be Pressure Washed?
Pressure washing can be effective on some surfaces, but it isn’t suitable for every roof.
Some roofing materials, coatings and structures can be damaged by excessive pressure. High-pressure cleaning can potentially remove protective coatings, damage surfaces or force water into areas where it should not go.
The condition, material, design and pitch of the roof should therefore be considered before deciding how it should be cleaned.
In many situations, a lower-pressure chemical treatment can provide a safer approach to controlling organic growth.
How Does Roof Treatment Work?
The treatment is applied across the affected areas of the roof using appropriate application equipment.
Once applied, the treatment begins working on moss, mould, lichen and other organic growth. The cleaning process is gradual rather than an instant visual transformation.
Depending on the amount and thickness of growth, it can take several months for the roof to naturally clear and reach its full cleaned appearance.
This gradual process is one of the key differences between a roof treatment and pressure washing.
How Long Does Roof Treatment Last?
The results of a roof treatment depend on a number of factors, including the roof’s condition, surrounding vegetation, exposure to moisture and the amount of organic growth present.
As a general guide, a treatment may remain effective for around 12–18 months, although this can vary from property to property.
Roofs with heavy or established growth may require a further treatment once the initial growth has died back and the roof has had time to naturally clean.
Regular maintenance treatments can help keep the roof looking cleaner for longer.
What Does Roof Treatment Remove?
Roof treatments are primarily used to target organic growth such as:
- Moss
- Mould
- Lichen
- Algae
- Other organic surface growth
The effectiveness and expected results depend on the type of roof and the condition of the existing growth.
Very heavy growth may not disappear immediately. In these situations, allowing the treatment time to work is an important part of the process.
Roof Treatment vs Roof Pressure Washing
Roof treatment and pressure washing are two different approaches.
Pressure washing uses water pressure to physically remove dirt, moss and other contamination from a surface.
Roof treatment uses a chemical treatment to target organic growth and allows the weather to gradually remove the dead material.
Neither method is automatically suitable for every roof. The correct approach depends on the roofing material, roof condition, pitch, accessibility and type of contamination.
For roofs that are not designed or suitable for pressure cleaning, treatment can be a much more appropriate option.
What About Steep or Difficult Roofs?
Roof cleaning can involve significant working-at-height risks, particularly on steep, fragile or difficult-to-access roofs.
A professional assessment should consider access, roof pitch, surface condition and the appropriate equipment required to complete the work safely.
Not every roof should be walked on or pressure cleaned, and in some situations the safest approach may be a treatment method that minimises unnecessary traffic on the roof.
What If Your Property Uses Rainwater?
Special care is required where a roof collects rainwater for household use.
Roof treatment products should not enter a rainwater collection system used for drinking or household water.
If your property has a rainwater retention or collection tank connected to the roof, let your contractor know before any roof treatment is carried out.
At Metro Water Blasting, we do not carry out roof spray treatments on roofs that collect rainwater for household use.
If a roof wash is being carried out on a property connected to a rainwater tank, the tank may need to be disconnected before the work and remain disconnected until the roof has been adequately flushed by rainfall. The exact requirements should be discussed before work begins.
When Should You Consider Roof Treatment?
A roof treatment may be worth considering if you notice:
- Moss growing across the roof
- Black or green organic staining
- Lichen developing on roofing materials
- Mould or algae growth
- Increasing organic buildup
- A roof that is not suitable for pressure washing
Treating the problem earlier can be preferable to allowing heavy growth to establish across the entire roof.
Professional Roof Treatment
Choosing the right roof cleaning method is important. A roof should be assessed based on its material, condition, pitch and existing organic growth before deciding how it should be treated.
At Metro Water Blasting, we provide professional roof treatment and exterior cleaning services, using appropriate low-pressure treatment methods where suitable.
If your roof is showing signs of moss, mould or lichen growth, contact us to discuss the most suitable cleaning option for your property.