Its likely that this powdery white material is efflorescence, which is the migration of salt to the exterior of a permeable material, such as brick, creating a layer. When moisture passes through a wall, or when water is expelled due to heat or hydration, this mechanism pushes salts to the surface. Depending on the extent of the harm, these bricks can be cleaned or replaced.
How do I know if my render needs cleaning?
Pressure washers are capable of removing algae, moss, dirt, and other types of build-up from your render quickly and easily.
