Mould and algae growth on exterior surfaces
Mould and algae growths have become a more common nuisance in Nordic countries in the pass decades.
Mould spores thrive in damp and warm conditions, so the risk of moulding is bigger on years when the fall is long and rainy and the winter is warm. On a warm winter the relative air humidity is significantly bigger than on a normal cold winter. Mould spores can maintain the ability to grow even on difficult weather conditions. Dirt that accumulates to the exterior surface can affect the quality of the surface. If the surface becomes dirty and after that is exposed to dampness for a longer period, the growth of microbes and moulds can be much more excessive than on an equivalent clean surface.
Mould and fungi growths do not only appear on painted surfaces, but can also appear on wood, plastic, brick, stone, concrete and even on glass surfaces. Due to the increased level of mould and algae growths, the exterior surfaces require regular maintenance and cleaning. The problem is mostly aesthetic and does not create structural damages. The facades that become dirty are also a challenge to paint manufacturers. Finnish paint manufacturers and product developers have an extensive experience of exterior paints and painting.
The raw materials are always selected to have the best suitability on the intended use. The raw materials are selected for exterior paints so that the paint surface does not increase the growth of mould and algae and they contain anti-moulding agents to protect the paint surface. The number of chemicals used in the paint is however restricted by strict international and national environmental, health, etc. regulations. Thus, the protection against moulding on the surface is limited.
Most common mould types, such as. black mould, is washable from the surface. Uula Washing Agent can usually remove the mould from the surface without damaging the paint surface. It must be taken into consideration when washing wooden surfaces, not to excessively water the structures, especially when a highpressure washer is used.
Extensively dirty surface and voluminous mould growth can be cleaned with Uula Mould Cleaning Agent. Re-painting the surface is recommended after this. If the surface is new, un-painted and wooden, we recommend to prime the surface with Uula Anti-Mould agent or with Uula Exterior Primer before painting