Quality waterproofing additives are about the same price as latex paint, so water-repelling modifiers do not significantly increase the cost of a paint job. These additives also increase surface durability, prevent color fading, and reduce mold and mildew problems. They make painting easier by minimizing brush marks and roller drag and enhance the flow of paint over the surface as well. The slick, electrostatic-free finish of paint that contains waterproofing additives allows dirt and grime to be washed or wiped away easily--a valuable bonus.
Measure and pour four parts of latex paint into a plastic bucket.
Insert and tighten a mixing paddle attachment into the chuck of a two-speed electric drill. Set the drill to the lowest speed. Immerse the paddle in the paint and turn the drill on.
Add one part waterproofing agent to the latex paint in the bucket. Pour the additive in slowly. Continue mixing until the additive is thoroughly combined with the paint. Remove the paddle.