Why Do I Need a Primer?

Primer/sealers work to eliminate stains (including stains from water and fire damage) cover wood imperfections, hide wallpaper designs and serve as a foundation coat on metals over which a finish coat is applied. They also seal the surface evenly so a topcoat will have uniform gloss.

There are three basic types: alkyd-based, water-based and shellac-based. The alkyd and water types work well as stain killers and general-purpose primers on both interior and exterior surfaces.

The shellac-based type blocks out the widest variety of stains, including knots and sap streaks in new wood, and adheres to slick surfaces such as glass and tile. This type is recommended for general-purpose priming on all interior surfaces, but should only be used for spot priming on exterior surfaces.

Acrylic or vinyl-acrylic latex’s are the most frequently sold water-based primers, but vinyl-based types are available. The term “water-based” includes vinyl, acrylic and vinyl-acrylic copolymer types. Acrylic block fillers are used to prime concrete block.