How to Apply Polyurethane to Wood Floors

February 17, 2023, by: Rob Parsell

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

• Sawshub.com – New to woodwork? Get started with these simpler projects
• Pete’s Hardwood Floors – Pete explains why you might not want to stain your own floor.
• www.minwax.com – Great products and great resources.
• www.addicted2decorating.com – Great in-depth DIY post

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.

About the Author:

Rob Parsell

Rob joined the Home Flooring Pros team in 2014 and is a freelance writer, specializing in flooring, remodeling and HVAC systems (read more).

“I’m the son of an interior designer and picked up an eye for design as a result. I started hanging wallpaper and painting at 14 and learned enough on the job to be the general contractor on two homes we built for our family and did much of the finish plumbing, electrical, painting, and trim work myself.”