DIY Guide: How to Refinish Hardwood Floors

If your hardwood floor has seen better days, and you think it might need a complete refinish, don’t worry. With a little know-how (and a lot of elbow grease) this is a job you can do at home. If DIY is not for you, knowing the process it takes to bring your floor back to life can help you determine which path to take -- whether refinishing or replacing -- and an understanding of what to expect along the way. This guide will walk you through every step of the process -- from determining if a hardwood floor refinishing is the best option for you, to adding the last coat of finishing product.

Is Your Floor Hardwood to the Core, or an Imposter?

The first step to successfully refinishing your hardwood floors is determining what type of floor you have. This might seem simple, but there are many varieties of flooring that masquerade as hardwood but are really partially or entirely made up of other materials, and each one requires a different refinishing technique.

The first hardwood lookalike is laminate. Laminate Plank Flooring is made of synthetic materials, layered and embossed with a grain pattern, meant to mimic the look and texture of natural wood. It’s typically pretty easy to tell if your flooring is made of laminate, as it simply feels like a hard plastic. Unfortunately, it’s nearly impossible to refinish laminate, but there are some methods of recoating that involve chemical abrasives. These methods are a long shot, however, and are not recommended by the flooring experts at The Good Guys.

Engineered Wood floors are another alternative to solid hardwood, made of a thin layer (or veneer) of hardwood, bonded to a layer of cheaper material, typically plywood. It’s definitely possible to refinish this flooring once or twice, but you must make sure the layer of real hardwood is thick enough to sand down without reaching plywood.

When working with engineered hardwood, you typically require about 1/8” of veneer in order to refinish. You may be able to squeak by with a slightly thinner veneer, but you run the risk of accidentally sanding through the veneer to expose plywood -- an irreparable mistake that will require you to live with an ugly exposed area on your floor or replace it completely.

Finally, solid hardwood floors are made of a solid plank of wood and are therefore the best candidate for refinishing. Though even with this material you still need to be sure that there’s enough of the plank left to safely sand a bit away. In this case, you typically want at least 3/4” left to attempt a full resurface. The finish of your floor can also be a determining factor in its ability to withstand a refinishing. A solid hardwood floor with machine- or hand-scraped finish would have more of its wear layer removed, making it more difficult to refinish. Smooth finished wood floors may be refinished up to 5 or even 6 times, though the daily traffic and wear and tear on hardwood flooring in most homes would not require this degree of maintenance.

How To Tell If Your Hardwood Floor Will Withstand a Refinish

A solid rule of thumb is that a typical solid hardwood floor can be refinished four or five times before it needs to be replaced, so if you know your floor’s history, you may not need to measure its remaining thickness.

Engineered hardwood floors can be a bit more tricky, as cheaper options will have minimal veneer that can’t even stand up to one round of refinishing, but if you have a receipt, box or model number, you may be able to look up how thick the floors were, to begin with. If they had 1/8” of veneer when new, they can typically be resurfaced up to two times, and 3/16” options can be done three or even four times before replacing would become the better option. When refinishing an engineered wood floor, it is not recommended to machine- or hand-scrape the finish, due to their thinner wear layers.

How Thick Are Your Floorboards?

If you don’t know your floor’s history, the easiest way to find how much material you have left is to look for a floor grate or vent that you can remove to expose the floorboards. If you don’t have any such openings, the next best option is to remove a threshold from a doorway as there are typically gaps between rooms that will expose the end of a board or plank.

Finally, if you still can’t tell, you can remove a piece of baseboard trim from the wall in the room that’s meant to be refinished. The baseboards aren’t typically removed during refinishing, so there will be a bit of a raised area underneath if the floor had been resurfaced previously. This method is a bit risky though; the baseboards may have been replaced when the floor was previously refinished for aesthetic reasons, and you still won’t know the current thickness of the floor.

Should You Recoat or Refinish Your Floors?

Once you know what type of floor you have, it’s a good idea to evaluate if a total refinish or a more subdued screen and recoat is necessary. A recoat simply involves roughing up your floor with a gentle sanding screen. and applying a new protective covering. This is a lot easier and much more inexpensive than refinishing but only fixes problems in the surface-level protective covering. On the other hand, a refinish will take care of moderate marring and discoloration but will require a lot more time, money and effort.

The best way to know if your floor should be recoated or refinished is to run a simple test. Find two areas on your floor and tape off a square of about 6 by 6 inches The first should be an area that represents the heaviest flaws you have in your floor to see if they’re repairable with a recoat. The second should be in an area that’s regularly exposed to cleaning products, such as window cleaner overspray, oil-based cleaners, or other heavy detergents.

It’s important to test an area that’s exposed to household cleaners as over time the floor will get imbued with those materials and a polyurethane finish coat won’t adhere to the floor properly. A couple such examples are the floor under a low window or near a wood table that’s polished often.

IMPORTANT NOTE: Only do this test if you’re sure you want to alter your floor in some manner. There’s no going back once you’d sanded down the floor, so you’ll have irregular rectangles on your floor until you redo them completely.

Test for Recoating Your Hardwood Floor

Once you’ve selected two areas and taped them off, get a 120-grit screen and thoroughly sand the area. Then clean it off with a brush or vacuum and damp cloth, and apply polyurethane (see later in this article for a comparison of oil- and water-based polyurethane options). Let it dry, and try gently scraping it with a coin or other metal object. Don’t use anything sharp or pointed or press terribly hard, as you’ll scratch through even a solid coating. If you’re satisfied with the finish and it doesn’t flake off when you gently scrape, go ahead with a recoat. If not, it’s time to start refinishing.

Uh Oh! This Job Calls for A Complete Refinishing

Necessary Materials:

Molding Bar or Putty Knife
Hammer
Masking Tape
Plastic Sheeting
Pencil
Drum or Orbital Sander
Sand Paper (30-40, Rough Grit)
Sand Paper (50-60, Medium Grit)
Sand Paper (80+, Fine Grit)
Wood Filler
Mineral Spirits (optional)
Floor Stain
Polyurethane Sealer

Step 1: Prepare The Room For Sanding

Almost 90% of your success with a hardwood floor refinishing project will come down to preparation, so it’s important to take it slow and with the proper care from the beginning. Start by removing the shoe molding -- also called quarter-round -- around the entire perimeter. Do this by gently inserting a molding bar between the floor and trim, and gently prying it away. Do not use a large crowbar or demolition bar as these will damage the molding. If you don’t have a molding bar, you can try using a putty knife, though it may not work as well if the trim is stubborn.

Also, remove any doors that will block wood thresholds, and go over the entire floor carefully searching for nails or other objects protruding up from the floor that may tear or damage a sanding pad. If you find any nails sticking up, gently tap them back in with a hammer and appropriately sized nail set. Make sure to keep track of where the holes are, and if you find any other imperfections keep track of those as well, so you can fill them in after your first round of sanding.

When you’re done, make sure to tape off any floor registers so they won’t get scratched if your equipment bumps into them. Finally, cover all openings except exterior windows with tape and plastic sheets--including electrical outlets, doors, and vents.

Step 2: Start Sanding

After you’ve prepped the room, it’s time to start sanding. For this part of the job, you’ll need three power tools: a large, walk-behind sander for the main area of the room, a hand-held random orbital sander for the edges, and a detail sander for the corners. It’s possible to do the corners by hand as well, but it will take significantly more time and effort.

Should You Use a Drum or Orbital Sander?

Walk-behind sanders come in two varieties: drum and orbital. When deciding which one to use, first consider your experience level. Drum sanders are very aggressive and can be difficult to control, so they are typically not recommended for DIY beginners. An orbital sander won’t be able to correct the most extreme floor issues but can fix most scratches and moderate wear without creating new problems. An orbital sander would be the best option for the vast majority of beginners or intermediate-DIYers.

Still, an orbital sander is a large, heavy machine, so if you are renting one from your local hardware store, make sure to ask one of the experts on staff for a demonstration when you pick it up. It’s often a good idea to practice at home before starting. Try it out with just the pads (no sandpaper) on a smooth cement surface, or do a few passes in an inconspicuous area of the room before starting on the main areas.

Floor Sanding Round 1: Rough Sanding

Do the first pass over the room using the walk-behind orbital with a rough sandpaper. 36-grit is typical, though you can use anything between 30 and 40 grit. Make sure to move the orbital slowly, smoothly, and evenly, and don’t stop in one area for more than a second or two. Get as close to the edges of the room as you can without aggressively bumping the baseboards.

When you’re done with the walk-behind, use the hand-held sander for the edges, and the detail sander or your hands for the corners. You’ll want to press as firmly as you can without stalling or slowing down the movement of the sander. When you’re done, vacuum the room to clean up excess dust before moving onto the next pass.

Correct Any Flooring Imperfections

Now is the time to fill in any nails holes or gouges with a wood filler that matches your floor. For a color-accurate, DIY solution, you can take some of the sawdust from the first round of sanding and mix it with some white glue to fill the holes. Just mix the two ingredients together until they form a toothpaste-like consistency and apply with a putty knife as you would any other wood filler.

Floor Sanding Round 2: Smooth Out Rough Edges

Next, sand the floor with a medium-grit sandpaper, such as 50 or 60 grit. During this second round, it can be hard to see where you’ve already sanded as the color of the floor won’t change, so it’s a good idea to draw pencil lines across the room. Then, as the pencil is erased by your sanding, you’ll know where you’ve already been. Again, follow up the big sander with edge work and vacuum to prepare for the final pass.

Floor Sanding Round 3: Finish Sanding

For the final sanding, use at least 80 grit sandpaper. You can even do two rounds if you want the smoothest finish possible--once with 80 grit, and once with 100. Follow up on the edges, and once again vacuum and clean up.

This time, take extra care to clean everything thoroughly, as the next step will be to apply a finishing agent. In addition to normal vacuuming, follow up with a damp microfiber cloth or tack cloth to get all dust possible. You may even want to finish with a rag dampened with mineral spirits. The exact method you use isn’t as important as making sure there is absolutely no dust or dirt on the floor that could mar the final finish. It should go without saying though, that you shouldn’t use any oil- or chemical-based cleaners on the floor as they may affect the ability of the final layer to adhere to the wood.

Step 3: Stain Your Floors

Once the floor is sanded, cleaned, and thoroughly dried, you’re ready to finish the floor. This is where you can stain the floor if desired, but properly staining hardwood floors is an art unto itself, so it is probably left for a separate article.

Step 4 (The Final Step): Seal Your Floors

Supreme Sealing: Is Water- or Oil-Based Polyurethane Best?

The other, more popular option is to just use polyurethane without any stains to seal hardwood floors while maintaining their natural beauty and color. If this is the route you choose, you have two options: oil-based and water-based polyurethane. Neither is superior to the other--it really just comes down to preference.

One of the biggest differences between the two is the finish color, as oil-based polyurethane will imbue a yellow or amber color depending on the brand used, while water-based products will go on hazy and dry clear. Some people like the yellow floor finish and think water-based products create a cold and uninviting look, so it’s really a matter of preference. Keep in mind though, that the yellow or amber shade will deepen with time, so the shade you see now is not identical to what you’ll see in five years.

In terms of application, each has pros and cons as well. Water-based products, for example, are thinner, so they will naturally go on more evenly and dry quickly. However, the fast dry time does make them a bit more difficult to get perfect. Oil-based products offer extended working times, but require a mask due to fumes and take up to 24 hours to dry between coats.

IMPORTANT NOTE:If you use an oil-based product, make sure to dry any soiled rags separately, or store them in a can covered with water. The natural oxidation that occurs as oils evaporate from a pile of rags can cause a fire under the right conditions! Finally, cost can be a differentiator. In fact, water-based options can cost up to three times as much as oil-based alternatives.

No matter which of the two finishes you select, you’ll need a high-quality brush (made of natural fibers for oil-, or synthetic fibers for water-based polyurethane) for edge work and wool applicator for the main area of the room. Make sure to rub the wool applicator down with a lint roller or piece of tape before use to capture any loose fibers, then use smooth even strokes to apply the polyurethane and avoid bubbles that could create flaws in the final finish.

Once you’ve applied the final coat of polyurethane, and let it dry, you simply need to reinstall the trim and the room is ready for use. If you’re using oil-based products, it’s recommended to use at least two coats, and at least three for water-based options.

Refinishing Hardwood Floors: a Satisfying Detail That Can Transform a Room

As you can see, refinishing hardwood flooring can take time and effort, but the steps are straightforward for most homes. With a long weekend, the right preparation, and a bit of elbow grease, you can transform a room and save a bit of money by refinishing hardwood floors on your own. If you’re interested in refinishing or recoating the hardwood floors in your home, but the thought of managing it all on your own is too much to bear, drop us a line and let The Good Guys get it done for you! Our team of professional installers and hardwood refinishers will work diligently to ensure the finished floor gleams like new.