How to Sand Wooden Stairs for Refinishing (60, 100, 150, 220 Grit Guide)

Wooden stairs endure heavy foot traffic and often show wear, scratches, and old finish. Sanding prepares them for staining, painting, or sealing, restoring beauty and safety. With the right grit progression, you can achieve professional results at home. This guide explains how to sand stairs step by step using 60, 100, 150, and 220 grit sandpaper.

Why Sanding Stairs Matters

Old finishes, dents, and uneven wear prevent new coatings from bonding properly. Sanding removes imperfections and smooths treads, making them safe, attractive, and ready for stain or polyurethane. Proper sanding ensures your refinishing project lasts for years.

Tools You’ll Need

• 60–220 grit sandpaper – coarse to fine for step-by-step prep.
• Orbital or detail sander – for wide treads and edges.
• Sanding block – reaches corners and risers.
• Vacuum & tack cloth – removes dust between grits.
• Wood stain or polyurethane – for finishing.

Best Grits for Stair Sanding

• 60 grit: Removes old finish and heavy scratches.
• 100 grit: Smooths surface after coarse sanding.
• 150 grit: Refines wood before finishing.
• 220 grit: Creates a smooth, stain-ready surface.

Step-by-Step Stair Sanding

1. Start with 60 grit. Strip old varnish and deep scratches using 60 grit (25-pack).
2. Smooth with 100 grit. Refine the surface using 100 grit (50-pack).
3. Refine with 150 grit. Prepare for stain or seal with 150 grit (25-pack).
4. Finish with 220 grit. Lightly sand for a polished surface ready to accept finish. Use 220 grit (100-pack).
5. Clean thoroughly. Vacuum and wipe down before applying stain or polyurethane.

Special Cases

For painted stairs, start with coarse 40–60 grit to strip paint before moving up. For softwoods like pine, avoid over-sanding with 220 grit to preserve stain absorption. Stair edges and corners may require hand sanding for precision.

Pro Tips

• Always sand with the grain to avoid visible scratches.
• Replace sandpaper often—old sheets burnish instead of cutting.
• Work stair by stair, completing all grits before moving to the next step.
• Seal stairs immediately after sanding to prevent dirt buildup.

Aftercare

• Reapply polyurethane every few years to protect against traffic wear.
• Clean with gentle wood-safe cleaners to avoid damaging finish.
• Repair scratches by lightly sanding with fine grit and resealing.

FAQs

• Can I use a belt sander on stairs? Only on large flat treads—otherwise use an orbital or detail sander for control.
• Do I need to sand between coats of polyurethane? Yes, lightly with 220 grit for adhesion.
• Can sanding fix squeaky stairs? No, squeaks come from loose joints—secure them before sanding.

Watch & Learn

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