Growth of algae on exterior painted masonry surfaces

• Published in: International biodeterioration 1988, Vol.24 (4), p.367-371
• Main Author: Wee, Y.C.
• Format: Article
• Language: English
• Subjects: Biodeterioration. Biofouling; Biological and medical sciences; Biotechnology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects
• ISSN: 0265-3036
• DOI: 10.1016/0265-3036(88)90022-X

Algal growth on exterior painted masonry surfaces is a tropical phenomenon, given the high temperature and rainfall of the region. In Singapore, the exterior walls of the many high-rise apartment buildings are fast becoming favourite habitats of subaerial green and blue-green algae. Where surfaces are slightly dampened during rains, followed by rapid drying, the green alga Trentepohlia odorata proliferates, giving the walls an orange tinge. The presence of this organism paves the way for the appearance of blue-green algae, that turns the surface black. On those that are wetter, other green or blue-green algae may appear, by-passing the Trentepohlia stage. The problem is an aesthetic as well as an economic one. Long-term control of such growths could be achieved by use of paints containing an effective biocide, however algicidal paints are not available on the open market. Screening of chemicals for the control of Trentepohlia was only possible after the successful culture of the organism in the laboratory. This led to trials with wooden panels and field tests on buildings, using paints incorporating promising chemicals.