Best Sandpaper for Refinishing Wooden Window Frames and Sills

Wooden window frames and sills often show signs of wear from sunlight, condensation, and constant use. Refinishing them restores both appearance and durability. The first step is sanding, which removes old paint or varnish and prepares the surface for a fresh finish.

Why Sand Window Frames?

Exposure to sun and moisture causes paint to crack, peel, or blister on window frames. Sanding removes failing coatings, smooths rough fibers, and ensures primer and paint bond strongly for long-lasting protection.

Tools You’ll Need

• Sanding block or orbital sander
• Sanding sponge for corners
• Vacuum with brush attachment
• Tack cloth or microfiber rag
• Silicon carbide sandpaper sheets

Best Grit Sequence for Wooden Windows

• 80 grit: Removing peeling paint and rough surfaces.
• 120 grit: Smoothing after paint removal.
• 180 grit: Refining the surface.
• 220 grit: Final sanding before primer or paint.

Step-by-Step: Sanding Window Frames

1. Start with 80 grit. Use 80 grit (25-pack) to remove peeling paint and rough fibers.
2. Smooth with 120 grit. Switch to 120 grit (50-pack) for surface refinement.
3. Refine with 180 grit. Use 180 grit (25-pack) to even out the wood.
4. Finish with 220 grit. Sand lightly with 220 grit (100-pack) before applying primer.
5. Clean up. Vacuum thoroughly and wipe with a tack cloth before refinishing.

Special Cases

For exterior frames, sanding should be deeper to remove weather-damaged fibers. For interior sills, light sanding with 180–220 grit may be sufficient before repainting.

Pro Tips

• Use sanding sponges to reach corners and grooves.
• Always sand with the wood grain to prevent scratches.
• Seal exterior frames quickly after sanding to protect from moisture.

Aftercare

• Apply primer and paint within 24 hours of sanding.
• Repaint frames every 5–7 years for long-term protection.
• Store sandpaper flat and dry for best performance.

FAQs

• Do I need to remove all old paint? Only flaking or peeling paint—firmly adhered paint can be feather-sanded smooth.
• Can I sand painted windows with glass installed? Yes, but protect glass with painter’s tape before sanding.

Watch & Learn

Sanding prepares wooden window frames for a flawless, durable finish. Explore our wood sanding collection to get the right grits for your project.