How to Remove Moss From Brick
If using bleach, test a small area first. Wait several days to make sure the brick doesn't change color.
Wear gloves and eye protection when using bleach.
Don't spray mortar joints with high pressure, because they could be damaged.
Moss tends to grow freely over brick walls, walkways and patios. When left unabated, it can cover your entire walkway, especially if it's in a shady area. There are several ways to remove it, but moss is persistent, which means that you may have to tackle it repeatedly.
Fill a spray bottle with ordinary household bleach. There's no need to dilute it with water.
Spray the moss with the bleach and watch as it turns white.
Wash the bleach off the brick with your garden hose. Stand far enough way that you are out of the range of bleach splatter.
Power wash the moss from your brick patios and walkways if it doesn't respond to the gentler treatment. In most cases, the moss will come off easier if it's still actively growing. Power washers are available from hardware stores and home centers, as well as from equipment rental outlets.
Set the power washer below 3,000 per square inch (psi) of pressure because any setting above that could damage the brick. Be sure to keep the wand at least 12 inches away from the brick when spraying.
Remove extra-stubborn moss by applying a mixture of 10 percent bleach diluted with water in a bucket. Use a hard-bristled brush to scrub the brick. Rinse with clean water.