How to Paint Exterior Window Trim

Weathered window trim is the first sign of a house losing its defenses against the elements. Peeling paint isn't just an eyesore; it's an open invitation for moisture to seep into your wood, leading to rot and expensive structural repairs. Addressing the trim now preserves the integrity of your home's envelope and restores that crisp, finished look that defines a well-maintained exterior. Successfully painting trim requires a shift in mindset: focus ninety percent of your energy on preparation and only ten percent on the actual painting. If you rush the cleaning or sanding, no amount of expensive paint will keep the surface from failing again in a year. When done well, this project creates a smooth, durable barrier that sheds rain and stands up to direct sunlight for years to come.

  1. Clear the Stage. Remove any window screens and trim away nearby foliage that blocks your access. Use a stiff-bristle brush and a mixture of water and mild detergent to scrub off dirt, spiderwebs, and loose debris.
  2. Strip Away the Loose. Use a carbide-tipped paint scraper to remove all flaking or loose paint. Work with the grain of the wood, being careful not to gouge the surface with the edges of the tool.
  3. Smooth to Accept Paint. Use medium-grit sandpaper to smooth out the transition between existing paint and the bare wood. Follow up with fine-grit paper to ensure the surface is uniform and receptive to the primer.
  4. Protect What Stays Clean. Apply painter's tape carefully along the edge of the glass where it meets the trim. Use a plastic putty knife to press the edges of the tape down firmly to prevent bleed-through.
  5. Bond Raw Wood First. Apply a high-quality exterior oil-based or bonding primer to all exposed, bare wood sections. This step is non-negotiable for ensuring the finish coat adheres properly to the substrate.
  6. Build the Durable Finish. Brush on two coats of high-quality exterior 100% acrylic latex paint using a high-quality sash brush. Allow the first coat to dry fully according to the manufacturer's time recommendations before applying the second.