By / In Existing Building Issues/ On
With our damp and warm climate, algae growth on external surfaces can be a problem. I generally just use a power washer every few years to clean the sheltered concrete areas where it can be a problem. However I discovered that the power washer was unable to remove the algae for my brick garden walls, probably as the brick was more porous than the concrete.
However lightly scrubbing the walls using a dilute solution of water and bleach provides an excellent result with little effort, see below.