Colourful paint can turn an old piece of furniture, an outdoor deck or another weathered wooden item from shabby into chic. However, when you're working with old wood, you need to properly prep the surface before you begin applying paint. If you don't follow the right steps, painted weathered wood quickly chips or discolours.
Kill any mildew growth on the weathered wood. Old wooden items are susceptible to mildew. Mildew appears as a fuzzy white or grey spots, much like common food mould growths. To kill the mildew, apply a 1-part bleach, 2-parts water solution to the spot and wipe clean. The bleach will discolour the wood, but this doesn't matter since you'll be painting anyway. Wear rubber gloves whenever working with bleach.
Sand the weathered wood with a medium-grit sandpaper. This renews the surface and fosters better adhesion.
Sand the surface again using a fine-grit sandpaper. This gives the surface a final buffing for a smooth finish.
Wipe down the wood with a moist towel. You don't want to saturate the wood, so make sure the towel is just barely wet enough to remove the sandpaper dust.
Apply an oil-based exterior wood primer using a paintbrush or roller. If you're painting on weathered cedar or redwood, use a stain-blocking wood primer, because these wood varieties tend to bleed through paint coverage and discolour the finish as they age.
Apply a coat of oil-based exterior paint to the weathered wood after the primer has dried.
Paint a second coat after the first coat dries.