How to Sand and Refinish Wood Stairs

Jan 29, 2024

Welcome to Floorsanding.co.uk’s guide on how to sand and refinish wood stairs. Refinishing wood stairs is an involved process but with proper preparation and using the right tools, you can breathe new life into old, worn staircases.

Below we have outlined a step-by-step process on how to refinish wood stairs, along with tips and advice on achieving a smooth, long-lasting finish. Read on if you’re looking to upgrade the look of your staircase without undergoing a full replacement.

Key Takeaways:

  • Carefully remove carpet, nails and old finishes from stairs with pry bar and hammer
  • Thoroughly clean stairs then sand with electric sander, starting with coarse grit paper
  • Vacuum dust between sanding with finer grits to smooth and prep for finishing
  • Stain stairs and apply 3-4 coats of durable polyurethane finish for desired look
  • Let stairs dry 24 hours between coats and avoid heavy use for 7 days after project

Refurbishing old wood stairs adds warmth, style and value to any home. While sanding and refinishing stairs requires physical effort, the right tools make the job easier. Safety should also be top priority when operating power tools and working on elevated surfaces.

The following sections take you through what’s needed to professionally sand and refinish indoor wood stairs. Make sure to read through all steps before starting for best results!

What You’ll Need

Here’s an overview of the tools, materials and safety equipment you’ll need on hand:

Tools

  • Pry bar
  • Hammer
  • Electric sander (orbital or belt with coarse to fine grit paper)
  • Shop vacuum
  • Paintbrushes
  • Paint trays
  • Rags
  • Drop cloths

Materials

  • Wood filler, wood putty
  • Sandpaper (40 grit, 80 grit, 120 grit, 220 grit)
  • Tack cloth
  • Stain (oil-based, gel or water-based)
  • Clear protective finish (oil-based or water-based polyurethane)

Safety gear

  • Dust mask & safety goggles
  • Knee pads

Other essentials

  • Painter’s tape
  • Mineral spirits (oil-based) or soapy water (water-based)

Purchase quality sandpaper assortments and check finishes for stair usage. Prepare enough stain and topcoat for 125-150 sq. ft. coverage. Having all materials and tools ready will streamline the process.

Prepping the Stairs

Proper prep work is crucial for getting wood stairs smooth and ready for new stain and finish. Here are the key prep steps:

1. Remove carpet, nails & old finish
Carefully pry up carpet staples and grippers then pull up carpet and padding. Use a cat’s paw nail puller and hammer to remove remaining nails sticking up from stairs.

Scrape off loose varnish, paint or shellac with a pry bar and stiff putty knife. Wear proper eye protection and respirator during demolition. Dispose of carpet and debris properly.

Prepping the Stairs

2. Clean and inspect stairs
Vacuum stairs thoroughly then clean with mild detergent and water using an abrasive pad. Let stairs dry completely. Check for cracked wood, splinters and loose boards that require repairs or replacement prior to refinishing.

Use wood filler or epoxy for minor cracks and holes. Sand smooth when dried. Consider calling a pro for structural staircase repairs.

3. Patch nail holes & imperfections
Dimpled areas around nail holes should be patched with wood filler, allow to dry, then sanded smooth. Use painter’s caulk for small cracks. Ensure stairs are in good condition before sanding.

Thorough prep removes dirt, flaws and things that might disrupt an even finish later on. It also allows you to examine the stairs for areas needing extra work.

Sanding the Stairs

With prep work complete, it’s time to sand the stairs. This removes remaining old finish or paint while leveling and smoothing the wood surface.

1. Start sanding with 40 or 60-grit paper
Attach coarse 40 or 60-grit sandpaper to your electric sander. Orbital and belt sanders work well for stairs as they sand flat and uneven areas. Always sand in direction of wood grain.

Use a light touch and overlap passes to evenly sand entire tread surface. Don’t press too hard to avoid uneven spots or digs. Make safety a priority when using power tools and working on stairs.

Sanding the Stairs

2. Thoroughly vacuum dust before progressing

Vacuum up all dust using soft brush attachment after initial coarse sanding. Sanding produces fine dust that must be removed before applying finer grit papers. Tack cloth surfaces to pick up remaining dust.

3. Move to 80 then 100-grit paper

Repeat sanding process using moderately coarse 80-grit paper followed by finer 100-grit to smooth scratches and prepare for finishing. Always vacuum thoroughly before moving to a finer grit.

Going over each step multiple times with 80 then 100-grit will ready stairs for stain by removing all scratches, marks and irregularities. Continue over balusters, risers and stringers as well.

4. Finish sand with 120-150 grit
For final smoothing, use very fine 120-150 grit sandpaper. Sand entire tread in direction of wood grain, overlapping passes. Vacuum and wipe clean with tack cloth when complete.

The stairs should now have a smooth, uniform bare wood appearance from top to bottom. Ensure no glossy areas remain before staining. Tack cloth surface one final time before staining.

Staining & Sealing the Wood

With freshly sanded bare wood, you can now apply your desired stain color and protective finish.

1. Use painter’s tape for a crisp paint lines
Carefully apply low-tack painter’s tape along the edges by upper flooring and bottom walls. This protects adjoining surfaces from drips and creates nice paint lines. Taping rounded balusters takes patience.

2. Apply stain with foam or cloth pad Use a foam brush, stain pad or lint-free cloth to wipe penetrating stain over stairs in smooth strokes following wood grain. Apply an even coat and wipe any drips right away.

Popular stair stain colors include medium oak, provincial, cherry or walnut. Let the first stain application dry per product directions before deciding if a second coat is needed.

Staining & Sealing the Wood

3. Seal stairs with 3-4 coats of clear polyurethane
Once stained, protect stairs using three to four thin, even coats of a durable clear satin, semi-gloss or gloss oil or water-based polyurethane. Abused stairs benefit from extra coat durability.

Allow sufficient drying per manufacturer directions in between finish coats. Lightly sand with fine 220-grit paper to smooth raised grain if any appears between coats

4. Remove painters tape after final coat
Carefully remove all painters tape after applying the final coat of finish. Dispose of dirty tape and clean up drips right away with mineral spirits/soap and water.

5. Let cure one week before heavy use

The polyurethane finish should harden adequately in 5-7 days. Avoid dragging heavy objects on steps during the one week curing timeframe. Place carpeting/rugs after 7 days when finish reaches full strength.

With some careful prep, persistence and the right equipment, refinishing stairs yourself can save thousands over replacement. The stairs make a strong visual impact and serve as a focal point in many homes. Protect them accordingly with a durable stain and finish!

We hope you found this guide on how to sand and refinish indoor wood stairs helpful and informative! Please contact us at Floorsanding.co.uk for assistance with your next stairs refinishing or hardwood flooring project.