How to clean hardwood floors without damaging the finish

Step by step

1. 1

   Find out what finish you have

   Look at an old stain or scratch. If the mark sits in a clear layer on top of the wood, you have a surface finish (polyurethane or urethane). If it goes into the wood itself, it's a wax or penetrating finish. The floor maker's care guide, if you have it, settles the question.

   Why: You're cleaning the finish, not the bare wood, and the right cleaner and repair method depend on which finish it is. The wrong product can dull or strip it.

2. 2

   Remove grit without water

   Sweep with a soft-bristle broom or a microfiber dust mop, then vacuum on the bare-floor setting with the rotating brush turned off. Get into corners and along baseboards, where grit collects.

   Why: Sand and grit act like sandpaper underfoot. A spinning beater bar can scratch the finish too.

3. 3

   Mist the cleaner onto the pad, not the floor

   Use a cleaner made for your floor's finish. Spray it lightly onto a microfiber pad or cloth, or mist a small area at a time, and wipe along the length of the boards.

   Why: This keeps the water on the boards to a minimum. Puddles soak into seams, swell the wood and leave the finish dull.

4. 4

   Wipe up wet spots and spills right away

   Go over any area that still looks wet with a dry microfiber cloth. Treat spills the same way as they happen: blot with a dry or slightly damp cloth, never leave them to sit.

   Why: Wood absorbs moisture and swells. Quick drying prevents white spots and cupped boards.

5. 5

   Let it dry before mats go back

   Wait until the floor is fully dry before you put rugs and mats back, and put felt pads under furniture legs while the room is clear.

   Why: Moisture trapped under a mat can mark the finish. Felt pads stop the scratches that come from chairs and tables sliding.

The finish decides the method

Solid and engineered wood floors are protected by one of two kinds of finish. A surface finish (polyurethane or urethane) is a clear film on top: stains and scratches stay in that film, and it takes cleaners approved by the finish maker. A wax or penetrating finish soaks into the wood: stains and scratches reach the wood itself, and these floors should not be damp-mopped with water-based cleaners.

What both share is that wood swells and shrinks with moisture. That rules out wet mops, steam mops and anything that leaves standing water. It also rules out vinyl and tile floor products and self-polishing acrylic waxes, which leave wood slippery and dull.

How often: the National Wood Flooring Association suggests sweeping or dust-mopping daily, vacuuming weekly, using a wood-floor cleaner about once a month, and a professional recoat every 3 to 5 years. Keeping indoor humidity at about 30 to 50 percent and the temperature between about 60 and 80°F limits gaps, cupping and splits.

Scratches, dull patches and stubborn buildup

On a surface finish, most scratches are in the urethane, not the wood. Cornell Cooperative Extension suggests urethane touch-up kits for these, and a cleaner made for urethane finishes, with a scrub pad suited to the finish, for stuck-on grime. A floor that looks dull and worn all over doesn't need a stronger cleaner: it needs a professional maintenance coat.

On a waxed floor, a white water mark can be rubbed gently with #000 steel wool and a little floor wax. Deeper marks may need light sanding, cleaning with fine steel wool and mineral spirits, then re-staining and re-waxing the spot. If a scratch or stain has gone through any finish into bare, gray or black wood, that's a refinishing job.

How stains behave on wood floors, and spot-treating rules

On a sound surface finish, most spills sit on top and wipe away if you catch them quickly. The trouble comes when liquid gets into seams, worn patches or a wax finish: water raises the grain and swells the boards, and it leaves white spots or a cloudy film in the finish. Pet urine is the classic example, because it soaks in and can darken the wood itself (see dog urine on wood and cat urine on wood). Mold growing where a floor stayed damp is covered in mildew on wood.

Whatever the stain, the rules are the same:

• Blot with a dry or barely damp cloth. Never pour liquid on wood.
• Test any cleaner or solvent in a hidden spot first. Alcohol softens shellac finishes, and acetone damages most finishes.
• Use the least water that works, then wipe the area dry at once.
• Don't use bleach, oxygen bleach or hydrogen peroxide as cleaners on wood finishes; reserve them for problems a refinisher has diagnosed.

By situation

Cleaning hardwood floors by hand

Work on your knees with two microfiber cloths: one lightly misted with your wood-floor cleaner, one dry. Clean a few boards at a time along the grain and dry them right behind you. It's slower but gives you full control over the moisture, which is useful in older homes or on worn finishes.

Cleaning hardwood floors with a mop

Use a flat microfiber mop, not a string mop and bucket. If your floor maker allows a mopping solution, wring the pad until it's barely damp: one engineered-wood maker says only a well-wrung mop. The floor should look dry within moments.

Using a spray mop and ready-made wood floor cleaner

Spray-mop kits sold with their own wood floor cleaner work the same way: a light mist and a microfiber pad. Check that the cleaner is meant for your finish (most are for polyurethane), wash or change the pad when it's gray, and don't use these products on waxed floors unless the label says so.

Engineered wood floors

The top layer is real wood, so the same rules apply: no steam, no flooding, no oil soaps or wax on a factory urethane finish. Follow the maker's care guide, because using an unapproved product can affect the warranty.

Waxed or oiled floors

Dust and vacuum as usual, but skip water-based floor cleaners. Use the cleaner and wax recommended for that finish, and rewax when the shine wears in traffic paths.

Kitchens and entryways

Grit and water do the most damage here. Put doormats at entrances and a breathable rug in front of the sink, and dry them out regularly so they don't trap moisture.

What not to do

• Don't wet-mop or let water stand on the floor. Standing water dulls the finish, can leave discoloring residue and swells the wood.
• Don't use a steam mop. The NWFA says steam and wet mops damage the finish and wood over time, and at least one floor maker excludes steam damage from coverage.
• Don't use oil soaps, wax, polishes or 'shine restorers' on a urethane finish unless the floor maker approves them. They leave residues that dull the finish and can interfere with a later recoat.
• Don't use vinyl or tile floor cleaners or self-polishing acrylic waxes. They make wood floors slippery and dull.
• Don't drag furniture across the floor. It gouges the finish. Lift instead, and use felt glides under legs.

Other methods that work

Diluted white vinegar

Guidance conflicts. One engineered-wood maker allows 1 cup of white vinegar per gallon of water on a well-wrung mop, where its product permits it. Other floor industry voices advise against vinegar because it can dull finishes over time.

Caution: Use it only if your floor maker's guide allows it. If you don't know, choose a pH-neutral wood-floor cleaner. More on what vinegar can damage.

Non-sudsing ammonia solution

The same engineered-wood guide allows 1/3 cup of non-sudsing ammonia per gallon of water, on a well-wrung mop, where its product permits it.

Caution: Only with the maker's approval, never mixed with bleach or vinegar, and with the windows open.

Baking soda paste for a stubborn spot

The American Cleaning Institute lists a baking soda paste for stubborn spots on wood floors. Rub gently and wipe off with a damp cloth.

Caution: It's mildly abrasive. Test on a hidden spot first, especially on a glossy finish.

Stain still there?

The floor looks streaky or hazy after cleaning

Usually too much product or a dirty pad. Wipe with a clean microfiber pad barely dampened with water, then dry. If haze stays, it may be polish or oil soap residue, which needs the floor maker's residue remover or a professional clean.

White spots or a cloudy patch appeared

That's moisture in the finish. On a waxed floor, rub gently with #000 steel wool and a little wax. On a urethane floor, a lasting white patch usually means the finish needs professional repair.

Boards are cupping or gaps are opening

That's moisture or dryness, not dirt. Aim for 30-50 percent indoor humidity, use a humidifier in winter, and call a flooring professional if boards are buckling.

Safety

• Never mix ammonia with bleach or vinegar-based cleaners.
• Ventilate when using mineral spirits, and keep them away from flames.

Never mix cleaning products; see chemicals you must never combine.

Questions

Stains on wood

• Cat urine on wood
• Dog urine on wood
• Mildew and mold on wood

More guides for this room

• How to clean area rugs by hand, in the washer or outside
• How to clean carpet at home, and get smells out of it
• How to clean tile floors (and the grout between them)