How to Sand Wooden Stairs Railings and Balusters (120, 180, 220 Grit Step-by-Step Guide)

Stair railings and balusters are often overlooked during refinishing projects, but they’re among the most visible features in a home. Because they are touched daily, railings collect dirt, oils, and scratches that make finishes wear unevenly. Sanding is the essential first step before repainting or staining railings and balusters. In this guide, we’ll cover how to sand stair railings and balusters properly using 120, 180, and 220 grit sandpaper.

Why Sanding Railings and Balusters Matters

Unlike flat stair treads, railings and balusters have curves and details that require careful sanding. Without it, paint or stain won’t adhere evenly, leading to peeling, blotching, or rough textures.

Benefits of sanding include:

• Smoother surface: Prepares detailed woodwork for a flawless finish.
• Better adhesion: Ensures stain or paint bonds strongly.
• Durability: Prevents peeling or uneven wear over time.
• Professional look: Enhances curves and details without losing definition.

Choosing the Right Grits

• 120 grit: Removes dirt, oils, and old finishes.
• 180 grit: Smooths rough sanding marks and blends surfaces.
• 220 grit: Final sanding pass for a paint- or stain-ready finish.

Tools and Materials You’ll Need

• Sandpaper sheets: 120, 180, and 220 grits.
• Sanding sponge or flexible pad: Perfect for curves and round balusters.
• Detail sander: Optional tool for tight spots.
• Tack cloth: Removes dust before finishing.
• Painter’s tape: Protects walls and stair treads from sanding.

Step-by-Step Sanding Guide

1. Begin with 120 grit. Use 120 grit (50-pack) to remove old finish, dirt, and scratches. Work with the curves, wrapping sandpaper around balusters for even coverage.
2. Smooth with 180 grit. Switch to 180 grit (25-pack) to refine marks and prepare surfaces for finishing. Pay close attention to transition areas where balusters meet the railing.
3. Finish with 220 grit. Apply 220 grit (100-pack) for a final, silky-smooth pass that ensures paint or stain applies evenly.

Special Considerations

Curves and details: Use sanding sponges or folded sheets to follow contours without flattening shapes.

Delicate wood: Avoid oversanding softer woods like pine, which can lose definition quickly.

Old finishes: If heavy paint is present, strip it first to avoid clogging sandpaper.

Pro Tips

• Sand by hand for detailed areas—machines can flatten profiles.
• Always sand with the grain, even on curves.
• Wipe dust away between grits to prevent scratches.
• Prime immediately after sanding to prevent dirt absorption.

Aftercare Before Painting or Staining

• Wipe railings and balusters with a tack cloth before finishing.
• Apply wood conditioner after 220 grit for even stain absorption.
• For painted finishes, lightly scuff with 220 grit between coats.

FAQs

• Can I skip 120 grit? Only if the surface is already clean and smooth. Otherwise, 120 grit is essential.
• Is 220 grit always needed? Yes—it ensures the best finish for both paint and stain.
• Do I need a detail sander? Not required, but it helps for hard-to-reach areas.
• Will sanding change the shape of balusters? Not if done carefully with light pressure.

Watch & Learn

Shop stair railing sanding sheets: Get 120, 180, and 220 grit sandpaper in convenient packs. Shop wood sanding sandpaper.

Closing Thoughts

Sanding stair railings and balusters requires patience and attention to detail, but the results are worth it. By moving through 120 → 180 → 220 grits, you’ll create a smooth, paint- or stain-ready surface that enhances your staircase’s appearance. With the right grit sequence and tools, railings and balusters can look professionally refinished and last for years to come.