Over time, stained wood doors get scratched, dingy and dull. You've no doubt priced new doors: They're expensive to purchase and install. Painting over your old stained doors extends their useful life for years, covering the worn surface with a bright new coat, whether you choose fresh white, warm brown or an intense, fun colour. The keys to painting over stained wood doors are attention to detail, meticulous preparation and quality tools and materials.
Clean the door using a scrub sponge and mild detergent. Even if the surface looks clean, chances are there's a substantial accumulation of furniture polish, dust and grime.
Fill dents, gouges and nail holes with carpenter's wood putty. Allow it to dry for at least one hour.
Sand the door with a flexible sanding sponge or 120-grit sandpaper until the entire surface looks dull and feels smooth when you run your hand over it. Brush or vacuum away sanding dust.
Prime the door with water- or solvent-based stain-blocking primer. Use a 5 or 7.5 cm (2 or 3 inch) brush for panel doors or a brush and 15 cm (6 inch) trim roller for flat doors.
Sand the door lightly after priming, especially if you've used water-based primer. This ensures a very smooth surface. Brush away the dust.
Apply caulk to gaps in panels or at joints by applying a bead of caulk and then smoothing it down immediately with your fingertip or a damp rag.
Apply two coats of satin or semigloss paint with a brush or roller.
Quality water-based paint is much easier to use than oil-based paint and tends to be more durable.
Open a window or use fans to dissipate paint fumes, especially when you're using oil-based primer or paint.