Cleaning exterior brickwork such as walls, paths and fences on a regular basis not only keeps the brick looking fresh and new, but also increases its lifespan. Moss, mildew and layers of dirt trap moisture that degrades the surface of the brick. Removing grime will preserve your brickwork for years to come.
Condition is Everything
Before cleaning, inspect the brickwork for any damage. Cracks, chips and missing chunks of mortar can allow water to seep past the surface, causing permanent damage. Make any necessary repairs before cleaning the bricks so that water and detergent don’t make the problem worse.
Test It Out
If you plan to use any detergent on the bricks, test an inconspicuous area prior to cleaning. Spray or apply the cleaner on the brick, scrub as you would during cleaning and then rinse. Check the brick after it dries to make sure the detergent has not caused any discoloring.
Spray It Away
Use a pressure washer to remove surface dirt and grime. Take care not to damage the masonry by using the highest pressure or holding the sprayer too close to the bricks. Keep the pressure below 3000 psi. In most cases, pressure washing will be enough to clean the brick. If it is stained or heavily soiled and the sprayer does not leave the brick clean, you may need to use a detergent.
Use a commercial brick cleaning solution to remove stains and grime, or make your own. For grime, mix equal parts laundry detergent and water. For stains, especially those caused by moss, mix one part bleach with 10 parts water. Or, create a paste that you can spread on the brick by mixing one part salt and one part dishwashing liquid and then adding just enough water to create a thick paste. Start at the bottom of the wall and work your way up, letting the detergent stand for five to 10 minutes before scrubbing with a brush and rinsing.
Blast It Off
As a last resort, you can use abrasive blasting to remove stains and dirt. This process can damage bricks and mortar if not done properly. It is not appropriate for historic or soft bricks. This type of work is best done by a professional. If you decide to do it yourself, test a small area first to make sure the abrasive does not pit or damage the brick. Abrasive blasting options include sand, nut shells, cherry or peach pits and glass beads.