Sanding Wooden Floors Before Refinishing: Complete Grit Guide (36–220)

Refinishing hardwood floors is one of the most dramatic ways to refresh a room, but the results depend heavily on proper sanding. A flawless finish starts with following the correct grit sequence. This guide walks you through everything from coarse leveling to fine smoothing so your stain and finish go on perfectly.

Why Sanding Floors Matters

Wood floors accumulate scratches, dents, and old finish over time. Sanding removes these imperfections and creates a uniform surface that accepts new stain or polyurethane evenly. Skipping grits or rushing leads to swirl marks and uneven coloration.

Tools You’ll Need

• Drum sander for main floor areas
• Edge sander for corners and baseboard areas
• Vacuum with HEPA filter
• Respirator mask and hearing protection
• Wet/dry sandpaper sheets for detail hand sanding

Recommended Grit Sequence

• 36 grit: Heavy material removal, stripping old finish, leveling uneven boards.
• 60–80 grit: Intermediate sanding to remove 36-grit scratches.
• 100–120 grit: Smoothing and prepping for stain.
• 180–220 grit: Fine finish sanding before applying polyurethane.

Step-by-Step Process

1. Clear the room. Remove all furniture, rugs, and vents. Seal doorways with plastic to contain dust.
2. Start coarse. Use 36 grit with the drum sander to strip old finish and flatten boards. Overlap each pass by half the drum width.
3. Refine with medium grits. Switch to 60 grit (100-pack) sheets or belts to remove deep scratches, then follow with 80 grit.
4. Smooth with fine grits. For even stain absorption, sand with 120 grit (50-pack) sandpaper, focusing on blending edges with the main floor.
5. Finish with ultra-fine. Before sealing, use 220 grit (25-pack) wet/dry sheets on edges and detail areas. This ensures a silky surface ready for polyurethane.
6. Vacuum thoroughly. Remove all sanding dust with a HEPA vacuum, then wipe floors with a damp microfiber cloth.
7. Apply finish. Use your chosen stain, followed by at least three coats of polyurethane for durability.

Special Cases

For engineered hardwood, avoid going below 80 grit to protect the thin veneer layer. Always test a small area first to ensure you don’t sand through the surface.

Pro Tips

• Always sand in the direction of the wood grain to minimize swirl marks.
• Change sandpaper frequently—dull sheets burnish wood and cause uneven stain absorption.
• Keep the sander moving; stopping in place can gouge the floor.
• For dark stains, finish sanding at 100–120 grit to leave micro-scratches that help stain penetrate evenly.

Aftercare

• Wait at least 24 hours after final polyurethane coat before light foot traffic.
• Replace felt pads under furniture to prevent scratching.
• Vacuum with a soft-bristle attachment to maintain finish.

FAQs

• Can I refinish floors without sanding? Products exist for chemical etching, but sanding yields far better results.
• How many times can hardwood be sanded? Solid hardwood can usually be refinished 4–6 times, depending on thickness.
• Should I wet sand floors? No, only dry sanding is recommended for wood floors to avoid swelling.

Watch & Learn

With patience and the right grit sequence, your wood floors can look brand new again. Explore more coarse sandpapers, medium grits, and fine finishing sheets to cover every stage of your floor project.