Tips for Sanding Exterior Oak Wood Moulding

Cleaning and Preparation

• Removing all surface dirt from the moulding before you begin sanding ensures you don't force grime into the wood fibers. A clean surface also reveals any damage to the trim that might require replacement or repair before you expend the effort on sanding. Use a tri-sodium phosphate cleaner and nylon scrub brush to clean the oak. An old toothbrush works well for cleaning inside any decorative etching or scrollwork on the moulding. Let the oak dry completely before sanding because wet wood doesn't sand as smoothly as dry wood.

Old Paint Removal

• Several options are available for removing the old paint or stain. Sanding works well on blistered paint or thin coats of paint or stain. Heavy paint and stain often requires pressure washing to fully remove it. The overspray from the pressure washer can remove paint from nearby exterior surfaces, so choose this method only if you are repainting the entire wall. Scraping works well but it is the most labor intensive method for removing thick paint layers. Use a metal paint scraper on flat sections of the moulding and a sharpened chisel or screwdriver to scrape inside decorative scrollwork. Scraped and pressure-washed oak moulding still requires sanding before you can apply a fresh coat of paint or stain.

Sanding Method

• Use a disk sander to remove any remaining paint and to smooth the rough, weathered exterior of the oak trim. Begin with a rough-grit sandpaper and gradually reduce the grit until you are a using a fine-grit paper in the sander. Fine-grit sandpaper leaves the oak feeling smooth and gives it a satin-like texture. Fill in any cracks or nail holes with wood putty before the final sanding. Once the putty dries, sand over it so the repairs are flush with the surrounding moulding.

Staining and Painting

• Apply a mildew-resistant primer to the trim if you are using a solid paint color. Allow the primer to dry completely before painting. Primer and paint adheres best to a slightly rough surface so it isn't always necessary to sand the oak until it's completely smooth. Staining doesn't require a primer. Stain is preferable for oak that is still in good condition. Rough oak doesn't absorb the stain properly and will still feel rough after staining, so sand the moulding completely smooth before attempting to apply the stain.