Roofs are exposed to many aggressions, such as polluted air that contains sulfur, chlorine compounds and nitrogen compounds that lead to the appearance of acid rain, variations of mineral salts, dust or soot. These atmospheric pollutants accelerate the degradation process especially when the impurities on the roof are not washed by rain.
A roof should be kept clean. Even dust accumulation can be a cause of degradation, by maintaining moisture on the surface of the roof for too long. Other type of debris, such as leaves, twigs, bird feathers etc. contribute to the roof`s degradation as well. On the other hand, a dirty roof is also unsightly and can make the entire house losing its appeal.
But let`s go back to the initial question: do certain types of roofing materials attract debris?
It is not actually about attracting debris, but keeping debris on their surface for a longer time. For example, debris tends to slip or be removed more easily by wind and rain from a sloped roof, than from a flat roof. Also, a metal tile roof, with a smooth surface, will keep its appearance cleaner than a ceramic tile roof, which due to the specific porosity of the material, can retain dirt and even promote the development of moss and algae, if the tiles are not cleaned periodically.
Roof cleaning should be included in the annual maintenance of any type of roof. Even if there are roofs made from materials that do not retain dirt, they still have a drainage system that has to be cleaned. If gutters get clogged by debris, they will be more prone to corrosion and cause unwanted water ponds and infiltrations. For this reason, it is recommended to remove debris using a brush and then check the drainage system using water from a garden hose. In case of need, it is advisable to clean the entire drainage system (the downspouts too!)
In general, roofing materials must be cleaned with a soft brush and water at low pressure; impurities in the areas seriously affected by the dirt can be washed with special detergents, preferably eco-friendly, to prevent harming the roof and the surrounding vegetation. Rinsing should be done from the roof ridge to the gutters, after the detergent has taken effect.
Biocides, chlorine, bleaches and common detergents are risk factors for the health of plants, so it is recommended to take special protective measures if you use them for cleaning your roof.
- Apply biocide or repellent treatment in favorable weather conditions (in the absence of wind and precipitation).
- Prior to the application of the treatment, you should water the plants in the immediate vicinity of the roof and even protect them with foils that prevent contact with the chemical solutions and their infiltration in the soil.
- Also be very careful about using these solutions, as they are corrosive and can destroy some roofing materials. Make sure you consult with a Potomac roofing specialist before cleaning your roof, or leave the entire operation in their hands (highly recommended!).