Moss can damage brick walls over time, and make brick patios slippery. Regularly removing any accumulated moss will help keep your brick wall or patio looking new.
When removing moss, there are three main options. Any option should work, it just depends on the size and scope of your project which one you should pick.
For small areas, consider killing moss with bleach
On a day with no wind, fill a spray bottle with bleach. Saturate the moss with bleach, the bleach will turn the moss white. Then use your garden hose to rinse off the moss.
There are two main problems with this method: the possibility of staining your clothes when using the garden hose, and the possibility of killing nearby plants and grass.
However, for very small areas, if you dilute the bleach with a lot of water from your hose, this should not be a concern.
For somewhat larger areas, or for delicate brick that may not be able to withstand a lot of stress, consider removing the moss with a stiff nylon scrub brush and a solution of 1 part bleach to 9 parts water.
Be sure to wear gloves when working with the bleach solution, and rinse the area thoroughly with a garden hose when complete.
Once again, because you are working with bleach, the same drawbacks apply. However, since the bleach is already diluted, there is less of a threat to surrounding plants and lawns.
The final option is to use a power washer to remove the moss from your brick walls or patio. You should never use more than 3000 pounds of pressure when washing brick.
Also, be sure to keep the wand at least 12 inches away from the surface of the brick at all times.
This option for moss removal is the quickest method. However, it can damage older bricks, so pick another option if you own historic home.
Pressure washing to remove moss may also not be appropriate if the seams between your brick patio are not filled with mortar, just sand.
However, if your patio or wall was made from modern bricks and mortar, this is a great solution.