Brick should be sealed to reduce the affects of climate changes and pollution. Waterproofing sealants can be purchased at major hardware stores or concrete companies. On newer brick apply once every 5 to 10 years. On older brick, where the surface is porous the sealant will have to be applied more frequently, such as every 4 to 7 years.
The length of time between coats will depend on the porosity of the brick and weather conditions (prevailing winds, etc.). Chimneys will need the sealant applied more often than the brick work of the house. Chimneys tend to deteriorate due the fact that they get wet and stay wet for longer. Blowing winds then force rain water into small cracks in the bricks or the pointing. Any freezing will then cause the bricks and the mortar to crack. This sealant can also be applied to any stucco finish around the base of the house or on the chimney.
The sealant will need to be reapplied when water no longer forms “beads” on the wet surface. The sealant penetrates the brickwork and forms an invisible barrier protecting the brick against moisture penetration and attacks of airborne pollutants. What’s more, the sealant resists dirt accumulation and retards the formation of efflorescence. It is also breathable and water-based. It can be easily applied using a hand pump type sprayer with a tank.