Any home exposed to the elements will become stained and discolored over time. This is caused by the accumulation of grit, dirt, and airborne pollutants. Even worse, a home’s exterior can be host to mold, moss, or algae. While dirt and discoloration cause no structural problems, mold and moss growth can weaken bonds between bricks.
Pressure washing can remove deep stains and unwanted growth. It is useful for cleaning brick, asphalt, metal siding, and wood. It must be performed carefully, however, as it can remove things you wish to keep, like sealer or paint.