How to Sand Hardwood Floors Before Refinishing (36–220 Grit Workflow)

Refinishing hardwood floors can transform a dull, worn surface into a rich, like-new finish—but the key lies in proper sanding. The right grit sequence removes old coatings, levels boards, and prepares wood for stain or polyurethane. Here’s a detailed step-by-step guide to achieve professional-grade results on your own.

Why Sanding Floors Matters

Hardwood floors endure years of foot traffic, scratches, and fading. Sanding removes the top layer of old finish and minor damage, revealing fresh wood beneath. Proper sanding ensures even stain absorption and smoothness before sealing. Skipping grits or rushing the process can leave swirl marks or uneven coloration.

Recommended Tools

• Drum or belt floor sander for main surfaces.
• Edge sander or detail sander for corners and walls.
• Wet/dry sandpaper (36–220 grit range).
• Vacuum, tack cloth, and microfiber mop for cleanup.
• Wood stain, sealer, and polyurethane finish.

Ideal Grit Sequence

• 36 grit – Strip old finish and level floorboards.
• 60 grit – Remove deep scratches and even out texture.
• 100 grit – Smooth surface and prepare for stain.
• 220 grit – Final pre-finish sanding for ultra-smoothness.

Step-by-Step: Sanding Hardwood Floors

1. Prepare the space. Remove furniture, vents, and baseboards. Seal doorways with plastic to contain dust.
2. Coarse sanding. Begin with 36 Grit (25-pack) paper to remove old varnish and high spots. Move the sander steadily with the grain, overlapping each pass slightly.
3. Intermediate sanding. Switch to 60 Grit (50-pack) for a smoother surface. This stage removes lines left by coarse grit and starts to reveal uniform wood tone.
4. Fine sanding. Progress to 100 Grit (100-pack) wet/dry paper to refine texture. Use an edge sander with the same grit to reach corners and edges.
5. Final smoothing. Lightly sand the entire floor with 220 grit to eliminate micro-scratches before staining or sealing. Vacuum and wipe with a tack cloth between each grit change.
6. Apply finish. Once smooth and clean, apply wood stain if desired, then multiple thin coats of polyurethane. Lightly sand between coats with 220 grit for a glassy final surface.

Special Cases

For engineered floors with thin veneers, skip the coarse grits—start at 100 grit to avoid sanding through. For parquet floors, sand diagonally first, then finish with the grain for a consistent appearance. If deep gouges or stains remain after 36 grit, use a wood filler before continuing.

Pro Tips

• Always keep the sander moving—pausing in one spot can create gouges.
• Work in small sections and overlap edges for even results.
• Replace paper frequently—floor sanding wears down grit quickly.
• Vacuum thoroughly between grits to prevent embedded dust scratches.
• Sand with good lighting—side lighting reveals imperfections better than overhead light.

Aftercare

• Let polyurethane cure for 7 days before heavy foot traffic.
• Use felt pads under furniture to protect the new finish.
• Clean with hardwood-safe cleaners only—avoid steam mops or harsh chemicals.
• Recoat every few years to maintain gloss and durability.

FAQs

• Can I sand floors by hand? Not effectively—use a rented drum or orbital sander for even results.
• How do I know when to change grits? When all previous scratches are gone and the surface feels uniform to touch.
• Do I need to remove all old stain? Yes—any leftover patches will cause uneven color when restained.

Watch & Learn

By carefully sanding hardwood floors through 36 to 220 grit and finishing with light polishing between coats, you’ll achieve a smooth, durable, and visually stunning surface worthy of any professional refinish.