Case 1

Remedial

The use of algicides, toxic washing and repainting of walls every few years is useful in preventing such growth to stay permanently on the façade. High water pressure jet may be used [2-3].

Algae, mosses, fungi that grow on the external façade of the building can be readily killed by a number of chemicals. Some of these chemicals leave a toxic residue to deter further colonization. One of the following method can be used:

1. Apply a solution of domestic bleach and after a few days, scrub or scrape off the dead material which should come out from the surface easily;
2. Spray fungicide or algicides on the growth in accordance to manufacturer’s instructions and coat with water repellant and paint;
3. Treat it with 5% solution of magnesium silicofluoride crystals in water.

Apply coatings over surface to prevent water from retaining on the external wall.