When refinishing a hardwood floor, it may seem natural to approach stair treads as part of the floor itself and sand them with a flooring edger. This is a risky approach, because the edger wheels can fall off the tread and force the sanding disk to bite too deeply into the wood. Moreover, the edger leaves swirl marks that become more pronounced at the limits of its reach in the corners of the tread. There's a better way to refinish stair treads. It involves more time, effort and materials, but it leaves the treads in better condition.
Strip the existing finish with chemical stripper. Paint the stripper onto the treads and risers with a paintbrush, let it work for 20 minutes, then scrape it off before it dries with a paint scraper. Wipe the stripped wood with a rag soaked with water or a thinner that will neutralize the stripper and let the wood dry out. Wear rubber gloves, eye protection and a respirator throughout the procedure.
Sand the treads and risers with an orbital sander and 80-grit sandpaper. A sander with a triangular pad will allow you to sand the corners more efficiently than one with a square pad, but you can also scrape the corners with a pull scraper.
Use a pull scraper by setting the blade in a corner and pushing down on the tool with one hand while you draw the blade along the grain of the wood with the other. If the blade is sharp, the scraper will remove a thin layer of wood without leaving scratch marks.
Replace the sandpaper on the sander with 100-grit paper and sand the treads and risers again. Work the sander as far as you can into the corners. If you've scraped the corners, however, there is no need to scrape them again.
Make one more pass with the orbital sander, this time using 120-grit sandpaper. The fine paper will remove the swirl marks left by the coarser paper.
Sand the treads by hand with 120-grit sandpaper. Fold a sheet of sandpaper around a sanding block and sand along the grain of the wood. This procedure will remove the fine swirl marks left by the sander.
Things You Will Need
- Chemical stripper
- Paint scraper
- Rubber gloves
- Orbital sander
- 80-, 100- and 120-grit sandpaper
- Pull scraper
- Sanding block
- If your stairs have molding or features that are difficult to sand by hand or with an orbital sander, use a rotary tool fitted with a drum sanding accessory. It is an efficient tool for detail sanding.
- If the finish is especially hard and the stripper doesn't remove all of it, do a preliminary sanding with a belt sander and 50- or 60-grit paper. Always run the belt parallel to the grain of the wood, and don't let it linger in one place or it may wear a depression.
- The fumes from chemical strippers can be dangerous. Advise people to stay out of the room in which you are working, and keep the room well ventilated.