Algae is a tiny plant form. It has no roots nor leaves. As a result, it can grow on almost any surface. Algae thrives in places that are damp and have strong sunlight. Therefore, the external facade of buildings, roads, and walls are perfect habitats for algae to spread in ideal conditions.
In sunny and damp Singapore, algae is common problem in most homes. Algae are usually characterised as green to blackish marks on walls, roofs, and external facade of buildings, and external pipes.