Masonry Magazine August 2001 Page. 28
The result is that water penetrates the masonry, sometimes even to the building's interior. It can stay in and behind the masonry, uncontrolled, causing stains, damage, or both. The masonry's natural durability is neutralized. Architects have used exterior devices to limit water penetration. Not only practical, ornaments on older architecture added beauty. Projecting water tables, window heads and other features helped divert water away from the masonry and wall openings.
Today, cost constraints often sacrifice these useful features. Sometimes, these features are used for ornamentation, but their functional value is lost.
Even with good design, you can't keep water out completely. Considering the damage water does, it makes sense to protect valuable masonry.
FILM FORMING AND PENETRATING WATER REPELLENTS
Film-forming water repellents do just that. They create a surface barrier that shields the masonry from water.
Film-formers cover masonry pores with a continuous surface film. They usually create a gloss or sheen.
This approach has a drawback. Though the film keeps water from