How to Apply Polyurethane to Wood Floors

Welcome back to our Ask the Home Flooring Pros feature where we answer your most frequently asked questions. This week we look at how to apply polyurethane and specifically the best way to apply it to a wood floor, rather than any other kind of woodworking project.

We show you all the tools you need and how much they cost, then we take you through the steps of applying water-based and oil-based polyurethane to your hardwood floor, both how to cut into the edges of your flooring and cover the larger central areas efficiently. Before you embark on applying polyurethane yourself it’s worth asking yourself how much you are saving doing the work yourself vs the time saved hiring a professional. If in doubt take a minute to get advice and free estimates from local contractors.

Tools, Supplies & Costs for Applying Polyurethane

Here’s what you’ll need, with prices:

  • White vinegar: $2-$3/quart
  • Tack cloth: $12-$20
  • Polyurethane sealer, oil-based or water-based (see can for coverage): $22-$28/quart or $55-$70/gallon
  • 5” to 3” bristle brush (natural bristles for oil; synthetic for water): $7-$15
  • Roller or applicator pad with handle: $18-$40
  • Extra roller cover or pad made: $6-$15
  • Respirator with a vapor cartridge if using oil-based polyurethane only: $25-$40

Applying Polyurethane to Hardwood Floors: Step by Step

Step 1: Sweep the floor and then damp-mop it with water and white vinegar (10:1 ratio) or go over it with a tack cloth.

Step 2: Use the 5″ to 3″ brush to apply polyurethane to wood flooring edges, and use the roller or pad to apply it to the center of the floor.

Let’s look at each of the elements in Step 2:

How to cut in the edges:

  1. Remove the baseboard trim (preferred) or cover it along the floor with painter’s tape
  2. Stir the polyurethane, but don’t whip it or shake it, to prevent excess air bubbles in it
  3. Start at the corner furthest from the doorway out of the room
  4. Dip the brush in far enough to cover 1/3 to 1/2 of the bristles, and clear polyurethane from the tip of the brush on the edge of the container
  5. Start along the edges with comfortable strokes of 10-14 inches, then double back twice in a tight “Z” pattern, so the backstroke and second front stroke slightly overlap
  6. Repeat on the next section of edge, overlapping slightly, and continue for 8-10 minutes

How to apply material to the center of the floor:

  1. Immerse your roll or pad in the polyurethane
  2. Start one foot from the edges of the first corner, and work polyurethane toward the edges, working with the grain of the wood
  3. Use comfortable back-and-forth sweeps of three to four feet with the roller or pad
  4. Alternate between edges and the center of the floor every 10-12 minutes because if the polyurethane edge dries, the place where you left off will show
  5. If adding one or two more coats, lightly sand the floor between coats with an abrasive pad (for water-based polyurethane) or steel wood (oil-based material)

How Many Coats of Polyurethane for Hardwood Floors?

The best practice is to apply three coats of polyurethane, allowing the floor to dry, and lightly sanding it between coats. Some finishers offer lower estimates for two coats, but your floor won’t have the same level of protection, and scratches will go through to the wood more easily. In short, you will save yourself a bit of work or a little money by opting to apply two coats. However, you will sooner be faced with the expensive task or refinishing your hardwood flooring.

And that’s it! Well that’s the practical theory anyway…staining wood floors is challenging and best left to the experienced DIYer or a flooring professional. Here are some helpful resources to help you decide

And before you go take a look at our guide to popular hardwood floor stain colors

You can also read our guide on how to refinish hardwood flooring.

13 thoughts on “How to Apply Polyurethane to Wood Floors

  • May 7, 2020 at 6:51 pm
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    We are just finishing up on a floor that’s 91 years old. It was all labor intensive but worth it in the end. It is not a single person job for sure. We mixed oil based stain to get a “custom” color. Sealing it with water based poly, 3 coats. It has taken bout 3 weeks but could have been finished within a week. My help had another full time job. All in all ,You want to be happy with end results because its kind of a one time only project. Hope this helps with a little insight.

    Reply
  • March 23, 2020 at 6:01 pm
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    Why does my hardwood feel and look gritty? We put on two coats, but didn’t sand between them. Is that the issue? If I lightly sand the floor now, will this happen when I put the third coat on?

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    • May 7, 2020 at 4:29 pm
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      Needs sanding. Then redcoat once more

      Reply
  • March 15, 2020 at 10:36 pm
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    I had my floors redone and now I’m seeing spots with no polyurethane, can I do them myself

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    • May 3, 2020 at 7:13 pm
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      I have the same situation. Help!

      Reply
      • September 18, 2020 at 3:53 pm
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        Let me guess, you used Water Based poly? That’s what happened the first time I did my floors. I learned my lesson and redid them over 10 years ago with oil. I believe they put down 3 coats. No more issues. Anyhow, I patched up little areas on my water based poly floors by going to home depot and buying a water based poly and a little Lamb Wool applicator. Because I noticed when they did my floor, they used wool pads instead of brushes or rollers. I mixed the poly and applied it to the spots with the applicator and left it alone. Nobody noticed once it dried.

        Reply
  • March 4, 2019 at 11:48 am
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    excellent list – thanks for publishing

    do you recommend a fresh roller/pad for each coat or do you reuse?

    Reply
  • October 9, 2018 at 1:44 pm
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    Is there a protective coating to apply to hardwood floors after polyurethaning them..chair marks are occuring.

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    • December 19, 2018 at 10:37 am
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      Felt pads help minimize scratches from furniture that slides around.

      Reply
      • September 4, 2019 at 9:59 pm
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        Can’t find an answer anywhere, do you have to “cut in the edges and corners on every coat or just the first?

        Reply
  • July 2, 2018 at 2:34 pm
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    How long does it usually take to dry completely after you’re finished applying?

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    • August 4, 2018 at 1:42 am
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      It depends on how many coats you apply. Once you apply one coat, it is ideal to wait at least 4-6 hours before sanding. However, if the coat is still tacky, wait for it to completely dry. It’s best advised to wait at least 7 days before applying carpet and furniture to the room.

      Reply
      • May 30, 2019 at 11:17 pm
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        What would be the best spray applicators for applying Polly. And can you cut Polly to get a better smoother finish when spraying, if so please advise me on a product that may be used

        Reply

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