How to refinish a hardwood floor

Wood flooring in rough shape? Before you call the pros, it’s good to know that you can refinish hardwood floors on your own with a handful of rentable tools

Strip hardwood is one of the most popular types of flooring—and for good reason. Most often found in straight lines, these boards offer a nearly endless array of options when you combine species, board widths, stains, and finishes. Few flooring options give you the ability to go from crisp, clean, and modern to warm, rustic and country quite like wood flooring. And beyond aesthetics, wood is easier to keep clean than carpet, plus softer on your back than stone or tile. But hardwood’s biggest appeal might be the thing homeowners dread thinking about most: refinishing it by sanding, a process that will restore wood floors to their original beauty time and time again. 

The finish on any wood floor is sacrificial and in time will need to be refinished to bring back that new floor shine. Modern, pre-finished hardwood flooring is coated at the factory and can look new for 10 to 30 years. But the coating on traditional site-finished flooring won’t last nearly as long. Grime, dirt, shoes, kids, and pets can beat up a floor’s protective polyurethane finish and show signs of wear in just a few years. Left unprotected, the wood below will start to get damaged too. The good news is that hiring a pro isn’t your only option when it comes to adding luster back to those floors. If you’re an experienced DIY and not afraid of a few days of serious labor, you can save quite a bit by refinishing hardwood floors yourself.

Can I refinish wood floors myself?

Yes, the tools a professional flooring contractor would use are available through rental centers or the rental department at a large home center. Everything you need, from the finish on the floor to the respirators you’ll want to wear while sanding, is easily found at most home centers. 

Still, there are a few instances when you’ll want to hire a pro. If you want a stained floor, that can take some practice to get consistent results and avoid blotchiness. If you’re planning to do the entire house, a professional crew will be faster and that’s less of a disruption to your family—remember you can’t be on the floor until about 24 hours after the final topcoat of polyurethane has cured. If your floor is uneven, you’ll want a pro’s experience to level it out, and the same goes for complicated patterns like a chevron or large medallions. While water stains are easy to sand out, pet stains often penetrate the wood very deeply and can’t always be sanded out. Consider having a pro replace the section of the floor under a pet statin before sanding.

Before you think about refinishing a floor, think about screening it

Most hardwood floors are finished with polyurethane that may, or may not, be resting on top of a stain. In some instances, you can revive the floor by removing and then adding a new polyurethane finish without, technically, sanding the wood. The pros call this “screening” or “screen and coat.” 

The method requires some hand sanding in corners, but most of the work happens with a 16- or 17-inch-wide floor polisher or buffer—think: what janitors use to shine up school hallways. The buffer, fitted with an abrasive sanding disc that looks like a window screen, spins around the room cutting through the polyurethane finish. Buffing machines rent for about $65 per day, and the different grit discs cost about $10 each. 

A gallon of polyurethane finish, enough to cover about 500 square feet, is about $52. If the floor is in good structural shape, considering screening it before doing a full sanding. Whether you do this DIY or pay a pro, the cost of a screening and recoating is significantly less than sanding.

How to refinish hardwood floors

If you’ve decided a floor screening won’t do, follow these steps to refinish your hardwood floors.

Step 1: Make a plan

Sanding a floor means removing everything in the room. Anything left behind—like artwork or a wall-mounted TV—will get caked in a layer of sawdust. If you can’t remove it, cover it with plastic and tape it securely to limit dust infiltration. Then plan to not be back in the room for about 3-4 days.

Step 2: Gather supplies

The traditional method of refinishing a floor relies on three key tools that you’ll have to rent:

  • A drum sander for the field
  • An edger for getting close to the walls where the drum can’t reach, and
  • A buffer to sand between coats

A newer version of a floor sander uses a series of random orbit sanders. It’s more DIY-friendly, less aggressive, and does the job of the drum and edge sander, but it’s much slower—more on that later.

You can rent all of these tools, plus the sandpaper they need—in 60, 80, and 100 grit—at the rental center. You’ll need some hand tools like a scraper, sandpaper, and a nail set and hammer to sink any proud fasteners. You’ll also need to buy the supplies to polyurethane the floor. 

A respirator and eye protection are good ideas when sanding to limit exposure to dust. If your base molding has a shoe, remove it carefully with a prybar. You’ll re-install it after the floor is finished. Leaving it in place means the molding gets beat up by the edger, leaving scuff marks that you’ll have to touch up with paint after. Tape off doorways and any vents in the room to keep the dust confined to the space you’re working in.

Step 3: Use the drum sander

Generally, you want to move the drum sander in the direction of the wood’s grain, not perpendicular to it. Once the room and floor are clear and you’ve added a box fan to an open window, so it pulls dust out of the room, you can start sanding. 

Begin with the 60-grit sanding belt and make at least two passes over the entire floor, sanding away about an 11-inch-wide swath each time. Ask the rental center for a demo of the machine and watch clips online to learn how to raise and lower the drum and how to work the machine across the floor at a steady, even pace so you remove a consistent amount of wood. Empty the bag of sawdust when it swells or after each pass around the room.

Step 3: Edge the walls

When you rent this machine, ask for a nylon pad to slip between the motor and the 7-inch sandpaper disc. That acts like a shock absorber, which reduces the chance you’ll gouge the floor. Now go around the room and sand any of the original flooring left by the drum sander. The goal is to remove the color and the finish and blend the seam where the edger and drum sander meet. You’ll also need to sand spots the drum was too big to get, like closets. Repeat the process until you’ve gone around the room twice with 60-grit paper. Change the paper often if the finish isn’t coming off and you find yourself forcing the machine.

You’ll notice the round edger disc leaves a crescent-shaped swath of flooring in the corners. Remove that by pulling a carbide hand scraper along the grain to flatten out the corners. You might need to do this after each round of sanding so the corners are as flat as the rest of the floor.

Step 4: Alternate between the drum and edger sanders again

Suck the floor clean with a utility vacuum before moving onto the next grit. Repeat process with the remaining two grits: Make two passes with the drum sander fitted with 80-grit paper then two trips around the room with the edger and its 80-grit paper. Vacuum the floor, then move onto the 100-grit paper on both machines. Check the corners and hand scrape as necessary to keep them flat.

As you move to the next grit of paper check for swirls or scratches in the floor you missed. Rest a flashlight on the floor so its beam casts across the wood. Any deep swirls left from the previous grit in the drum or the edger will be easier to spot. Check around the room. If you spot any, hand-sand them with 100-grit sandpaper, rubbing with the grain.

Step 5: Screen the floor

Vacuum the floor again then wheel the drum and edger out of the room. Roll in the buffer, fitted with a 120-grit sanding screen. This screen’s job is to blend the entire floor together so the drum and edger sander’s marks are indistinguishable. It can take some getting used to when running the buffer; it’s more of a dance than trying to muscle the machine so ask for tips when you rent it. Run the buffer over the entire room along the wood’s grain, overlapping the previous course by a few boards.

Once you’re done buffing, leave the room and let the dust settle for about 15 minutes. It might be helpful to bring in a battery-powered or plug-in electric leaf blower to force the settled dust out of baseboard heat registers—with the room clear now is the time to clean and vacuum those too. If you had the window open to expel dust, close it now to avoid any debris blowing into the room and onto the finish. Vacuum the floor again.

Step 6: Prepare for the polyurethane finish

Walk across the room, following the grain of the wood, using a tack rag mop. This gathers up any last bits of dust the vacuum left behind so your finish coats lay flat on the floor.

Now set up for finishing: grab a clean, disposable aluminum roasting pan that’s wider than the synthetic-wool applicator you’ll be using to spread the finish. Usually, something wider than 12-inches will work. Flip the short edges of the aluminum up to act as a scraper. Place that on top of a scrap piece of cardboard that’s bigger than the pan. Fill the pan with enough polyurethane finish to coat the room. Use some blue painter’s tape to pat the wool applicator and pull out any loose fuzz. Set it aside on the cardboard. Have a foam brush or painting pad to handle the corners and edges of the room. Place this setup near the wall furthest from the door so you can work your way out of the room.

Step 7: Cut in

Use the foam brush or applicator pad to add polyurethane to the corners of the wall furthest from the door. Then run the finish along the edge between those two corners. Now add polyurethane to the ends of the boards so you’ve coated about as many boards as the synthetic wool applicator will cover in one pass—about 5-6. Pull the finish along the grain of the wood and brush out any pools that form. The goal is to work fast enough that the finish you’ve cut in is always wet.

Step 8: Spread the finish

Working quickly, while the corners and edges are still wet, dip the bottom edge of the synthetic-wool applicator into the pan and drag it along the aluminum scraper to remove the excess finish. Starting in the first corner you coated, place the applicator on the floor close to but not touching the baseboard molding. Now walk away from that corner towards the other corner, dragging the applicator behind your body as you walk. Keep the edge of the applicator closest to your body up at a slight angle so you pull and spread the finish as you walk. When you get to the far wall the handle of the applicator prevents you from getting tight to that wall. Pick the applicator up, place it against the wall and pull the finish towards the end of the first pass. Now starting from that wall, run over the entire first pass with a second pass.

Repeat the cutting in and spreading the finish in the field along the wall, picking up the pan and cardboard as you move. Handle any closets or nooks in the wall as you work and try to maintain that wet edge. With each secondary pass along the floor, make sure to blend a board’s width with the previous pass.

Step 9: Buff and vacuum

Let the first coat dry according to the polyurethane manufacturer’s recommendations on the can. Once the floor is dry, buff it with a 100-grit disc to knock down the finish. Hand sand any areas the buffer can’t reach with 100-grit sandpaper in corners, along edges, and in closets. Let the dust settle, vacuum the floor, then tack rag it again.

Step 10: Add a second coat

Following steps 7 and 8, add a second layer of polyurethane to the floor. You can repeat the process again for a third coat, which will leave you with a very durable finish. Most professionals will apply two coats. You do not buff after the final coat.

The easier but slower DIY alternative sander

For pros, a drum sander is the preferred way to sand a floor. It’s aggressive and takes off a lot of finish and wood in a single pass. For a novice DIYer, that can be too aggressive. You can cause serious damage to a wood floor if you’re not careful with a drum sander. Over the last few years, an alternative has emerged on the rental market: Random orbit floor sanders.

These sanders look more like a buffer machine. But underneath there are three or four sanding discs about 7-inches wide that remove an 18-inch-wide swath of finish. Those discs use hook and loop sandpaper, like the random orbit sander in your garage, and they operate the same way. 

The random pattern reduces the presence of swirl marks on the floor. The machine gets closer to the wall than a drum sander can so you’re left with little hand-scraping or sanding in the corners. Far less aggressive than a drum sander, the orbit sander is much slower. It might be the right solution to work at your own pace for a small to medium size room. Random orbit floor sanders rent for about $70 per day from the home center—about the cost of a drum sander but you wouldn’t have to rent a separate edger—plus your cost for sandpaper.

How much does it cost to refinish floors yourself?

If you’re going to refinish the floor expect the cost to start at about $1 per square foot. You’ll need to rent a drum sander ($70 daily); edger ($50 daily); and buffer ($65 daily). If you don’t already have a good utility vacuum, you’ll need to rent that too. A gallon of polyurethane finish, enough to cover about 500 square feet, is roughly $52. 

Factor in the sanding belts, pads, discs, applicators, brushes, painter’s tape and plastic sheeting, and that can add about $100 to $200 depending on the size of your project. 

Prices vary greatly from pros, but they might charge $3 to $5 per square foot to refinish your floor. So, it pays to get a few estimates before you decide to take the project on yourself.

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