How to Remove Polyurethane From Wood Floor

The first step in refinishing a wood floor is to remove the old finish. Removing the old finish is a complicated process because you have to take up the hard shell of polyurethane (or varnish, or whatever kind of gloss is on the floor) without damaging the wood underneath. Chemical stripping is one option, but it can be messy and unreliable; it's generally better to sand off the finish, which brings the added benefit of smoothing out the wood and opening up the grain in preparation for the new finish.

Things You'll Need

• Hammer
• Nailset
• Vacuum cleaner
• Drum-style floor sander
• 36-grit, 60-grit, 80-grit and 120-grit sandpaper for the sander

Instructions

1. Walk over the entire floor with your hammer and nailset, sinking any nail heads that are sticking up. Look for any other obstructions as well (splinters, debris) and remove them.

2. Thoroughly vacuum the floor.

3. Load your drum sander with the roughest grade of sandpaper (36-grit). Starting near one wall, begin running the sander at roughly a 45-degree angle to the direction of the floorboards, so you're cutting across the boards diagonally. The sander should dig into the polyurethane finish and take most of it off.

4. Sand in overlapping rows, working your way across the whole floor. Vacuum up all the dust.

5. Re-load your sander with the next-roughest level of paper (60-grit). Repeat the sanding process, but this time work in the opposite diagonal direction. This pass should take up the remaining polyurethane. Vacuum up the dust.

6. Re-load your sander with 80-grit paper and sand the floor in the direction of the floorboards. This should remove the crosshatch marks left by the previous diagonal sandings. Vacuum up the dust.

7. Sand once more using the 120-grit sandpaper, following the direction of the floorboards, to smooth out the wood surface.

Tips & Warnings

• Rent a drum sander at a home improvement or equipment rental store.

• Wear a dust mask while sanding.

References

• ThisOldHouse.com