How to Sand Wooden Stairs Without Damaging Edges (80, 120, 220, 320 Grit Step-by-Step Guide)

Wooden stairs add elegance and character to a home, but they also take heavy daily use. Over time, stair treads and railings can become scratched, dented, or worn down. Refinishing stairs is a great way to restore their beauty, and sanding is the most important step before staining or painting. In this guide, we’ll cover how to sand stairs effectively using 80, 120, 220, and 320 grit sandpaper, with tips to protect delicate edges and achieve a smooth, professional look.

Why Sanding Stairs Matters

Stair treads endure constant foot traffic, while railings and risers accumulate scuffs and dirt. Sanding removes surface imperfections, levels out uneven wear, and prepares wood to accept paint or stain evenly. Without proper sanding, finishes may peel, look blotchy, or highlight scratches.

Key benefits include:

• Better adhesion: Paint and stain grip securely to sanded wood.
• Smooth texture: Eliminates scuffs, scratches, and dents.
• Durability: Proper sanding helps finishes last longer under heavy foot traffic.
• Professional results: Creates even color and highlights natural wood grain.

Choosing the Right Grits

• 80 grit: Removes old finishes, paint, or varnish from stair treads.
• 120 grit: Smooths out scratches left by coarse sanding.
• 220 grit: Prepares stairs for a paint- or stain-ready surface.
• 320 grit: Final sanding pass for extra smoothness before clear coat or glossy finish.

Tools and Materials You’ll Need

• Sandpaper sheets: 80, 120, 220, and 320 grits.
• Orbital sander: Efficient for flat stair treads.
• Sanding block or sponge: Perfect for stair edges and risers.
• Vacuum and tack cloth: Removes dust between sanding stages.
• Painter’s tape: Protects surrounding walls and trim.

Step-by-Step Sanding Guide

1. Begin with 80 grit. Use 80 grit (25-pack) to strip away old finish or paint from stair treads. Sand with the grain and avoid pressing too hard on edges.
2. Smooth with 120 grit. Switch to 120 grit (50-pack) to refine scratches and level the surface. Use sanding sponges on curved railings and balusters.
3. Prepare with 220 grit. Apply 220 grit (100-pack) for a smooth, stain-ready finish. Pay attention to risers and edges where brush strokes will show most.
4. Finish with 320 grit. Use 320 grit (25-pack) to give stair treads and railings a silky smooth surface, ideal for clear coats or glossy paint.

Special Considerations for Stairs

Edges and nosing: Sand lightly to maintain crisp lines—rounded edges look worn and reduce safety.

Balusters and railings: Hand sand with sponges or wrap sandpaper around dowels to reach curves.

Painted stairs: Strip heavy paint layers before sanding for best results.

Pro Tips

• Work one stair at a time to stay organized.
• Sand with the grain to avoid visible scratches.
• Vacuum thoroughly after each grit to prevent contamination.
• Always wear a dust mask and goggles—stairs create lots of sanding dust.
• Prime or condition the wood after sanding for even stain or paint coverage.

Aftercare Before Finishing

• Wipe down stairs with a tack cloth to remove fine dust.
• Apply primer or wood conditioner immediately after sanding.
• For stained stairs, wipe off excess stain to prevent blotching.
• Lightly scuff sand with 320 grit between finish coats for extra smoothness.

FAQs

• Can I skip 80 grit? Only if the stairs are bare wood without old finishes.
• Is 320 grit necessary? For matte finishes, 220 grit may be enough. For glossy finishes, 320 grit is recommended.
• Can I use a belt sander? Avoid it—belt sanders can gouge stair treads. Use orbital sanders instead.
• How long does it take to sand stairs? Expect 2–4 hours for a standard staircase depending on size and condition.

Watch & Learn

Shop stair sanding sheets: Get 80, 120, 220, and 320 grit sandpaper in convenient packs. Shop wood sanding sandpaper.

Closing Thoughts

Sanding wooden stairs may take patience, but the results are worth it. By following the grit sequence of 80 → 120 → 220 → 320, you’ll prepare stair treads, risers, and railings for a flawless new finish. With proper sanding, your stairs will look beautiful, last longer, and feel smoother underfoot.