While masonry surfaces are generally solid and durable, small water droplets can seep into masonry and cause cracks during the wintertime. Masonry paints help seal these surfaces, protecting against long-term damage. Of course, to get lasting protection, you need to apply masonry paint properly. Masonry paint is typically elastomeric, meaning it is formulated to fill gaps and bond to rough surfaces. Elastomeric paints, however, are much thicker than regular paints, so you need the right painting equipment for proper application.
Put on rubber gloves.
Clean the masonry with a muriatic acid cleanser and a rag. If the surface is dirty, the masonry paint won't cover adequately.
Rinse the masonry surface, using a garden hose or a wet rag. Let the masonry surface dry for at least four hours. Masonry surfaces are very porous, and they can retain water for several hours. Do not proceed until you are certain the entire surface is dry.
Paint the surface with masonry paint and a heavy-nap roller. Masonry paints are thicker than normal paints, and a light- or medium-nap roller won't soak up enough of the dense liquid for proper application. Apply the paint in parallel lines. Move the roller over each parallel line three times to unload the roller, set the paint and smooth the finish. Allow 50-percent overlap as you paint the masonry surface.
Apply a second coat of paint if necessary after the base coat dries. Masonry paint usually covers adequately in one coat, but in some cases you might need a second application.