Should I sand down to the wood before applying Polyurethane?
Remove all rugs and furniture from the room. Check the floor carefully for any nails (pound these down below the surface), carpet staples or tacks (pull these). Any of these could rip your sandpaper, ruining the sheet. Rent a floor sander from an equipment rental shop. Traditional drum sanders do a good job but are quite heavy and take some getting used to. (It’s important to keep a drum sander moving all the time. They work fast and if left standing in one spot can quickly sand a groove in the floor that would be impossible to remove.) Consider a newer orbital sanders designed for floor refinishing that is easier to control. Whichever you choose, ask for a demonstration of how the sander works before you leave the rental shop. Get a good supply of sandpaper (in a range of grits–—36, 60, 80, 100) that will fit your rental machine. Many rental outlets will take back sandpaper you don’t use. Ask about it. Clip the heaviest-grit sandpaper (36 grit) into the sander. Run the sander over the
