There are two types of prefinished hardwood floors: solid wood, which is made of actual planks of real wood, and engineered wood. If you have the solid wood type, you can absolutely refinish it, usually between four and seven times before the floor would need to be completely replaced. Engineered wood can potentially be refinished, but this is wholly dependent on the thickness of the top layer of wood.
Prepping the Room
When refinishing a hardwood floor, you must remove all of the furniture and any other objects from the room. All windows should be opened to allow for proper air circulation, which is especially important for the staining portion of the job. The floor should be swept clean of any debris that might get caught in the sander, which could dig into the floor and cause scratches and gouges.
As long as the prefinished floor is made of solid wood, or engineered wood with at least a 1.5-millimeter or thicker top panel, you can use a heavy-duty drum or orbital sander to sand away the old finish. If your floor is engineered wood, but the top panel is less than 1.5 millimeters, you will need to sand by hand, though you should check with the manufacturer to see if sanding is safe at all. Once you finish sanding, all dust should be swept, and the floor should be wiped with a tack cloth.
Once the floor has been stripped of the original topcoat and stain, you have the option of completely changing the look of your room by opting for a different-colored stain. Of course, you also have the option of not staining at all, if you like the natural look of the wood. When you're ready to stain, ask someone to help you to make the job go faster. One person should apply the stain with a brush, sprayer or roller, and the other should wipe up the excess with a clean cloth. This will help to ensure an even coat and will also speed up the drying process.
Even if you decided to leave the floor unstained, you absolutely have to apply a protective topcoat over the floor to protect the wood and prolong the lifespan of your floor. Polyurethane is one of the most common choices for sealing hardwood floors, but it is very toxic, so you must take every precaution during this process. Protective gloves, goggles and a respirator are all required when handling polyurethane. This product is painted on with a foam brush, dried, sanded and reapplied two to three times. You may need three or four coats if you didn't stain the floor first.