Plant in Buildings
Other than algae and fungi, biological growth on building façades may also manifest in the form of mosses, ferns or small plants.
Mosses are small plants that form mat-like patches on the walls of old buildings. Ferns and other small plants growing on walls are much more visible forms of biological staining and should be removed prior to further weathering of the surface.
Strangling figs are plants that propagate through dispersion by birds. They usually grow out of crevices in walls, and their roots extend downwards towards the ground. They should be removed as soon as possible because the growth of their roots may exert pressure on the cracks over time, resulting in the widening of said cracks. Climbing figs, on the other hand, are usually deliberately grown on walls for aesthetic purposes. They require regular pruning in order to maintain their aesthetic qualities