Although bricks are durable enough to withstand exposure to the weather, they are porous, which means they absorb moisture and stains. To prevent bricks from absorbing excess water, apply a waterproofing sealant to vertical brick surfaces such as walls and horizontal ones such as brick pathways. In addition to waterproofing the brick, the sealant resists staining.
Wait until a day when the brick you want to seal is completely dry and rain is not predicted for the following 48 hours.
Open plastic tarps and lay them over any nearby shrubs, grass or other vegetation to prevent getting sealant on them. If you are sealing brick on a wall, place tarps at the bottom to protect walkways.
Fill a clean garden sprayer with a waterproofing brick sealant. Screw the top onto the sprayer and pump the handle six to 10 times to pressurise it.
Hold the sprayer at least 30 cm (12 inches) from the brick surface. Squeeze the trigger to dispense sealant in long, horizontal strokes, overlapping each stroke by 15 cm (6 inches).The brick will darken slightly as the sealant goes on, making it easy to see if you miss spots. Work your way along the brick in sections until all of it is sealed.
Examine the area for any accidental over-spray, such as on gutters or downspouts, and clean them up immediately with warm, soapy water and a sponge.
Wait at least an hour before removing the tarps and touching or walking on the brick surface.
Only apply brick sealant when outside temperatures are above 5 degrees. You can also apply brick sealant with a brush or a roller.