- Depending on the condition of your floor, you can use either a drum sander or an orbital sander to strip away the old finish. If the floor is very even and level with minimal warping, you can use a drum sander. Otherwise, or if you are unsure, an orbital sander is the recommended tool. Start with a medium-grit sanding pad, around 100-grit, to remove the finish. Once the finish is stripped, smooth the floor's surface with a 220-grit sanding pad.
- As you sand down the finish, you will be creating a lot of dust in the room. This has to be completely removed before you can restain the floor. Start by sweeping up the bulk of the dust with a push broom. Pay close attention to the corners and edges of the floor. The rest of the dust can be removed with a damp cloth. Check the bare floor for stains -- old pet stains and oil stains in particular -- if you see any, scrub the floor with a solution of 1 cup of trisodium phosphate mixed with 4 gallons of hot water.
- Once the floor is clean and dry, you can apply a fresh coat of stain. Start with the edges and corners of the room, as these are the most difficult to get at with a roller. Brush the stain onto the edges and corners of the floor, then rub the stain into the wood with a clean cloth. This will soak up any excess stain. Once you get the corners and edges taken care of, you can roll or spray the stain onto the center of the floor. Work in sections and wipe up the excess stain with a cloth. Always apply and wipe with the grain of the wood.
- The first coat of varnish is typically diluted with an equal amount of varnish thinner. This will ensure that the first coat dries quickly and gets very hard. The first coat of varnish may bubble slightly as it dries -- this is normal. Lightly sand the floor by hand with a 400-grit or higher piece of sandpaper, then wipe up the dust with a tack cloth. Paint on two to four more coats of undiluted varnish, allowing each coat to dry completely.