Damp areas on walls, especially where there is little sunlight. encourages the growth of mould and algae. To remove and help retard the growth of moss and algae, you will need the following materials.
A paint scraper;
A stiff brush;
Fungicidal solution for the exterior;
An inexpensive paintbrush;
Please note: It is very important to wear safety goggles and a face mask.
Start by removing larger clumps of moss and algae by using a paint stripping knife, then use a stiff brush to remove any remaining growth.
Dilute the fungicide according to the instructions and paint it onto the wall. Don't be stingy with the amount - coat it iberally.
Allow several days for the fungicide to kill off the algae, lichen or moss. It will darken as it dies off.
Brush away the darkened material and recoat the wall with the fungicide.