It is possible to paint over paneling with the proper preparation and the correct type of primer. Paneling has either a wood or vinyl veneer and usually a wood grain and grooves. Recognizing the surface and using the proper materials and techniques will yield a quality painted surface.
Prior to priming and painting paneling, it is necessary to thoroughly clean it with a trisodium phosphate cleaner. Use ammonia cleaner to remove all polishes and waxes, and allow the surface to dry. Fill in any unwanted grooves with wood filler if you desire a smooth look to the wall. Countersink any nails by holding a nail sink to the head of the nail and striking it with a hammer. This drives the head of the nail below the surface of the wood. Fill the holes with wood filler. After all the areas patched with wood filler have dried completely, use medium-grit sandpaper along the patches and any other textures in the wood grain. This creates a smooth surface ready for the primer.
Wood paneling that is 100-percent wood with a wood veneer requires an oil-based primer and paint. Look for what is referred to as a block-out primer or a primer-sealant. This type of primer blocks or seals the wood to prevent the stain from bleeding through. In an inconspicuous area of the paneling, test the primer for bleed-through. If no bleed-through occurs within a few minutes, the primer will work for your application.
Vinyl or Laminate Paneling
Oil-based primers and paints contain solvents that will damage vinyl veneer paneling. Use a latex primer on paneling that is vinyl or has a vinyl veneer. Tint the primer to a color slightly lighter than the color of the paint. Also, use latex paint with latex primer; do not paint over a latex primer with an oil-based paint. Choose primer and paint that is specifically marked on the label for use with a laminate surface for any type of laminate paneling.
Another option to change the look of your wood paneling is referred to as pickling. In essence, this technique bleaches the wood and stain of its natural color and serves to lighten a dark wood paneling. White paint is rubbed on and off the wood's surface. Two-step bleach, generally available at paint supply stores, is used instead of primer. Rub on a latex or nonyellowing alkyd paint for the top coat, using cheesecloth, and then promptly rub it off. Pickling stains the surface and brings out the natural wood grain.