Extend the life of your roof with a good clean

Is it useful to clean your roof or not?

Over the years, natural residues such as moss, lichen or algae form on every roof due to environmental influences. Many homeowners don’t like the look of a dirty roof and would like to remove it.

However, cleaning your roof is not always useful. The vegetation only affects the protective function of your roof if the rainwater can no longer drain away and penetrates the roof structure. In that case it is advisable to remove the vegetation from the roof. Also if the moss grows under the covering material, you should remove it. Mosses store water and this expands when it freezes, potentially causing damage.

Whether you give your roof a ‘cosmetic clean’ or remove the moss or lichen because of possible damage, the treatment only has a temporary effect. This will depend on factors such as the density of the trees and the location of the house. Lichen and moss like moist, so they will come back more quickly on the shady north side and under large trees than in sunny spots where the roof dries more quickly. You can consider cutting some trees to allow the sunlight to keep moss and lichen at bay.

Leave it to the professionals to clean your roof

We strongly advise that you ask a professional crafts(wo)man to clean your roof. The roof can be easily damaged if you use the wrong equipment and products. But climbing and working on a roof requires also specific protective equipment. Professional roofers can immediately check whether your roof needs repairs due to damage that occurred in rainy autumn or harsh winter.

A few roof cleaning tips

• Individual mosses and lichen can easily be removed with a broom instead of using chemical products (that are often detrimental to the environment).
• Be extremely careful with high-pressure cleaning as the powerful water jet can penetrate the insulation layer and cause damage.
• Don’t have your roof cleaned too often, as every cleaning involves a risk, and of course it is also a major cost factor.
• Roof cleaning is not advisable if the cladding material is damaged or too old. Carry out repairs first or consider a roof renovation.
• Roof coverings containing asbestos should only be treated by specialised companies because of the health hazard.

How to find a roof cleaning company?

Local specialist companies are a good bet because of their proximity and the warranty they offer. Be careful with traveling roof cleaning companies: they tend to clean the roof with a high-pressure cleaner and often cause damage when walking on the roof.

Note: In some countries, roof cleaning by a professional craftsman can be claimed in your tax return as a household-related service.

Giving your roof a new coating

Some homeowners have a primer applied to the roof after cleaning it, often containing biocides to slow algae growth, before they have the roof repainted. However, these biocides wash out and get into the environment. Special attention is required, as not all roofing materials are suited to be coated. In general, you can coat concrete and clay roof tiles and roof panels made of fibre cement.

Or replace the roof cover for long-term protection

For older roofs, a new cover can be the better option in the long term instead of cleaning the roof with all the potential risks of damage. Compare the prices of professional roof cleaning with subsequent sealing, with the material costs of new roofing.

New roofing has the advantage that your roof gets a visually attractive overhaul, and at the same time, you can increase the efficiency of the roof and your quality of living. You could, for instance, use the occasion to install skylights to allow more daylight into your home, or add thermal insulation to optimise energy costs or add photovoltaic panels to generate your own solar power.

Also here, check in your country if there are subsidies or tax cuts for environmental investments.