How to Re-Stain Oak Stairs

Sand the banister or handrail using a handheld power sander with coarse sandpaper. Begin at the top of the banister and work toward the bottom. Do not sand through to the bare wood. Go back to the top and sand again using medium sandpaper, then fine sandpaper and eventually ultra-fine sandpaper. Ultra-fine sandpaper leaves the wood smooth. Move the sander with the grain of the wood, which is usually lengthwise on the railing.

Sand each spindle or baluster using a sanding sponge. Spindles or balusters are the vertical posts between the steps and the handrail. Begin with coarse grit and switch to each of the progressively finer grits.

Sand the decorative pieces using a power sander on the larger, flat areas and a sanding sponge on the details and grooves. Begin with coarse sandpaper and sand again with each of the progressively finer grits.

Sand the stair treads, which are the flat, horizontal parts for foot traffic, and the risers, which are the vertical boards between one stair tread and the next, and sand any remaining wood material that you want to re-stain. Begin with coarse sandpaper on a power sander and sand again using each of the finer grits.

Vacuum the stairs with a hose attachment. Wipe every sanded area with tack cloth. When one side of the cloth stops removing sanding dust, turn the cloth over and refold it to expose clean areas.

Put on rubber gloves and stir the stain with a paint stir stick. Lift the stick out of the stain to check for buildup on the bottom of the stick. When none remains, the stain is mixed.

Dip a rag into the stain and squeeze out the excess. Rub the rag against the banister following the grain. Wipe it off following the grain using a clean rag. Repeat the staining procedure on the rest of the stairs, leaving the treads and risers for last. Let the stained staircase dry.

Stir the polyurethane finish gently with a stir stick until it is uniform. Dip a finish brush into the polyurethane and scrape it against the inside edge of the container to remove the excess. Brush the finish onto the banister beginning at the top and working down the stairs using long, slow strokes to prevent air bubbles. Apply finish to the spindles and decorative elements of the staircase working from top to bottom.

Apply finish to the top stair tread and riser, then work your way down the staircase. Let the polyurethane dry overnight. Apply two more coats of polyurethane to the whole staircase, letting the first coat dry before applying the second.