Refinishing Wood Floors: 4 Basics to Know Before You Sand

TL;DR: Those scratches aren't just cosmetic. Before you rent a sander, learn your finish, match the repair to the damage, test your stain, and reseal so it lasts.

_Last reviewed: July 2026 · 3 min read_

Before you refinish a hardwood floor, four things save you from an expensive mistake: figure out what finish is already on it, match your approach to how deep the damage is, test your stain somewhere hidden, and seal the repair with a fresh topcoat. Scratches that reach bare wood aren't just cosmetic — unsealed wood absorbs moisture and stains, so it's worth fixing properly.

How do I know what finish is on my floor?

Do a simple alcohol-drop test in a hidden corner. Put a few drops of rubbing alcohol on the floor and wait a moment. If the finish gets sticky or dissolves, it's likely shellac or lacquer; if a drop of water beads and nothing happens to alcohol, it's probably polyurethane; if your finger smudges a waxy residue, it's wax. Knowing the finish tells you which products and repair method will actually bond.

Do I need to refinish the whole floor or just sand the scratch?

Match the work to the damage. Surface scratches that haven't reached bare wood often just need a light hand sanding and a fresh topcoat in that area. Deep gouges that expose raw wood, or widespread wear, call for a full sand-and-refinish of the whole room so the color and sheen stay consistent. Spot-fixing a deep gouge usually leaves a visible patch — be honest about which one you have.

Why test the stain first?

Because wood tone varies board to board, and the stain color on the can rarely matches what you'll get. Always test your stain on a hidden spot first — inside a closet, under a rug, or on a scrap of the same wood. Let it dry fully so you see the true color. Guessing here is how people end up with a patch that's noticeably lighter or redder than the rest of the floor.

Do I have to seal the repair?

Yes. A repaired or sanded area is bare and vulnerable until you reapply a protective topcoat. The clear finish — polyurethane is the common choice — is what resists water, scuffs, and dirt and makes the repair last. Skip it and the fresh spot wears through and stains again within months. Apply thin, even coats and let each dry before the next.

Record the stain match

The stain color and topcoat you used are exactly what you'll need for the next touch-up — and almost impossible to remember a year later. Write them down. Okoniq Property Hub keeps your floor refinishing notes and stain match in one private place in your browser, with the rest of your home maintenance records. For scuffs on painted surfaces instead, see patching drywall.

Frequently asked questions

Can you refinish floors without sanding?

For floors with only light surface wear, yes — a chemical "screen and recoat" or a refresher product can renew the topcoat without a full sand. Deep damage still needs sanding.

How often can hardwood be refinished?

Solid hardwood can typically be fully sanded and refinished several times over its life; engineered wood has a thin veneer and tolerates far fewer. Light recoats can happen as often as needed.

How long before I can walk on a refinished floor?

You can usually walk on it (in socks) within a day, but wait several days to a couple of weeks before replacing rugs and heavy furniture so the finish fully cures.

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FAQ

How much does it cost to refinish hardwood floors yourself versus hiring a pro?

DIY refinishing typically costs $1 to $3 per square foot for sandpaper, stain, and polyurethane, plus $40 to $80 per day to rent a drum or orbital sander. Professional refinishing runs $3 to $8 per square foot and includes labor, dust containment, and experience that avoids common mistakes like sanding too deep or uneven stain application.

What grit sandpaper should I start with when refinishing hardwood floors?

Start with 36- or 40-grit for floors with deep scratches, old finish, or uneven boards, then move to 60-grit and finish with 80- or 100-grit for a smooth surface that accepts stain evenly. If your floor only has light wear and you're screening for a recoat, begin with 120-grit instead.

Can I change the color of my hardwood floor when refinishing?

Yes — once the old finish is sanded off and the bare wood is exposed, you can apply any stain color you want. Test multiple shades on hidden spots because the same stain looks different on oak, maple, or cherry, and older wood often absorbs stain darker than new lumber.

What are the most common mistakes when refinishing floors for the first time?

Skipping the alcohol test and choosing incompatible products, sanding unevenly by moving the sander too slowly in one spot, applying stain before the wood is fully dust-free, and walking on or placing furniture before the topcoat fully cures are the errors that show up weeks later as streaks, soft spots, or peeling finish.