How to Completely Refinish Your Hardwood Floors

Hardwood flooring gives a home a beautiful, warm look that's timeless. If they've been neglected, though, they can do the opposite. Old, worn-out, and badly scratched floors are an eyesore, but thankfully there's a way to bring them back to their former glory.

Even floors that have suffered water damage or have had the original topcoat completely worn off can find new life with proper refinishing. This article will explain some of the intricacies involved, as well as a step-by-step tutorial on how to completely refinish your hardwood floors to their original state.

Should You DIY Your Hardwood Floor Refinish?

While this job is labor-intensive, anyone with a little DIY knowledge and a lot of elbow grease can tackle it themselves and save thousands of dollars. Hiring a professional will cost between $3-8 a square foot depending on many factors like the state of the floors, type of wood grain, if staining is needed, and how many rooms you want to do.

An entire 2000-square-foot house can cost $6000-16,000 to refinish, but the majority of the cost is labor. Doing the job yourself means you're only paying for rental equipment, sanding paper, stain, sealer, and some miscellaneous items like painter's tape and cleaning supplies.

This brings the overall cost somewhere between $500-1000 for an average of 2-4 days work, which can be well worth the time and effort to save hiring a pro.

When to Refinish vs Seal Hardwood Floors

If your floors look like they are in rough shape or you want a fresh coat of stain on them, it's time to completely refinish them. If you only have some surface scratches, you may be able to simply seal them with a coat of water-based polyurethane or another finishing agent after a light buffing.

How can you tell? If the scratches don't go deep into the wood and are just surface level, rub some olive oil on them. If they nearly disappear and feel smooth, then you can get away with buffing your floors with a light sand and then applying your chosen finish. If you rub your finger over them and can feel an indent, you need to do a complete refinishing.

Buffing and sealing is a lot simpler, less time-consuming, and cheaper overall than refinishing your floors completely, and can be done in just a few hours with limited equipment. You'll need to rent a buffer or use a pole-sander to scuff the surface up lightly.

You also need to prepare the room as if you were going to do a full refinish job, but in the end you'll have brand new looking floors. If this is all your floors need, after steps 1 and 2 you can skip to the buffing stage.

Step 1 - Prepare the Space

Whether you are doing one room or an entire level, you need to clean and prep the room so that you can work without anything in the way. All furniture must be moved to a different location, including curtains, rugs, floor vents, and any shoe molding along baseboards.

To get the quarter round or shoe molding off, take a sharp utility knife and run along the edge where it meets the baseboard so when it's pried off, the paint lines attaching the two pieces of trim will come off with a clean edge.

Then, gently pry with a flat bar bit by bit all the way down the length of the molding, as the nails will slowly loosen. Number the molding lightly with a pencil, so you know how it goes back on.

Cover exposed floor vents and electrical outlets near the floor with painter's tape and plastic so that dust doesn't get in. Seal any other areas that you aren't working in with plastic sheeting to prevent excess dust from entering those rooms or areas.

You won't be able to keep dust completely at bay during sanding, but it will help.

Step 2 - Repair and Clean the Floors

Check the floors for any nail heads that have popped up and nail them down with a hammer and nailset, making sure not to dent the flooring. Fill any large holes or scratches with wood filler and a putty knife.

Don't worry about surface scratches, these will come out during the process of sanding, just take care of any large imperfections and dents that go deeper than the layer you'll be sanding off.

Vacuum your floors thoroughly and then clean them with a hardwood floor cleaner or a mixture of water and vinegar. This will remove any regular dirt and debris.

If you notice tougher gunk, stains, or greasy spots, use a de-greaser or TSP, and scrub the areas so that you are left with clean, bare wood.

Step 3 - Sand the Floor

Once the room and floors are prepped, you need to sand the floors with a drum sander. This equipment is very expensive to buy, but you can rent it for a day or two from most local big box hardware stores.

If you haven't worked with this kind of equipment before, get someone there to go over how to use it. It's fairly simple to use once you get the hang of it, but using it improperly can damage your floors by removing too much at one time.

The trick to this machine is to be constantly moving forward when it's on. It works by moving in one direction rather slowly, taking off a thin layer of flooring as it goes.

If you stop it in place while it's still on, it will continue to sand off the floor, leaving a permanent mark that you won't be able to patch easily. To avoid this, start at one end in a corner and work away in strips like you would with a lawnmower, making sure to turn it off when you need to reposition it.

For the first run-through, use 40-grit sandpaper to remove the majority of the top surface. After one pass, you'll be left with a rough, but clean surface where any major dents and scratches have been removed.

Always move with the length and grain of the wood, and overlap each area that you've passed by a board or two depending on their width (again, similarly to mowing a lawn).

Check your sandpaper after you've done approximately 20 square feet, replacing when necessary, and empty the dust bag regularly, as well.

Step 4 - Edge Sanding and Repeat Passes

Use an edge sander to get at the area near the baseboards, as the drum sander won't be able to get close to them. Use 40-grit sandpaper to achieve a uniform surface as the rest of the sanded floor.

Remember, your shoe molding or quarter round will be going back on the baseboards, but you still want to get as close to the baseboards as possible so that your floor is level all the way around.

Once you've finished one pass and edge sanded with 40-grit sandpaper, repeat this process with 60-grit, 80-grit, and finally 120-grit sandpaper with both the drum sander and edge sander.

Do not skip these steps, as transitioning from coarser grit to finer sandpaper is what gets out all of the imperfections into a smooth surface that's ready for finishing. Remember to vacuum well in between each stage of sanding.

Step 5 - Buffing the Floors

Even though you've sanded the floor with fine sandpaper, buffing is the final step that achieves professional results. Even 120-grit sandpaper will leave tiny sanding marks on the floor, so buffing them out makes the floors completely smooth.

While you can use a pole-sander, this is more time-consuming and laborious if you have to do multiple rooms or an entire level. An industrial buffer can make this job go a lot faster, but it can be very tricky to get the hang of as it needs to be moved in a circular, side-to-side motion that can be hard on anyone with a bad back.

Either method will use a 120-grit sanding screen lightly scuffed over the entire floor. Just one pass is enough to get the floor nice and smooth, but you can always check and do a second pass if you need.

Once the floors have been buffed, you can clean them in preparation for stain or sealer. Use a vacuum that's strong enough to pick up every bit of sand and dirt, as even a tiny hair will show up in your final stage.

After vacuuming, you should run over the floors with a sticky tack cloth which will pick up any small pieces of dirt, or hair that you may have missed.

Step 6 - Apply Stain (If Applicable)

Your floors are now ready for the final step of applying stain if you want to change the color or tone of the floors. If you don't, skip to the next step of applying the sealer.

The way you apply the stain will depend on the product you are using. Some more expensive products can be rolled on, but usually stain is applied with rags or lamb's wool, starting in a corner, and planning your exit to work your way out of the room.

You need to wipe up any wet stain as you go, moving with the grain, and making sure every area of the floor soaks it up evenly. Work in two foot sections and try to keep a "wet" edge to prevent any line marks from each section so they blend together.

You'll need proper foot wear and soft knee pads so you don't scuff the floors as you stain, and for after it's dried if you are doing a second coat (if you want it darker). Properly ventilate the room or wear a respirator mask when staining.

You may need to buff after applying the stain. Sometimes stain raises the tannins of the wood, and a light buffing will smooth the floors in preparation for your sealer which you can usually do after 24 hours. Always follow the product instructions for dry times.

Step 7 - Apply Sealer

Once your stain is dry, and you are happy with the color (or if you didn't stain at all), it's time to seal the floors. This is a protective coat that not only prevents scratching, but also acts as a water-repellent while adding a nice sheen to the floors.

Water-based polyurethane sealer is the most popular and available sealer on the market as it dries the quickest, is the easiest to apply, and has the lowest VOC's. Oil-based polyurethane is more durable, but dries slower and may yellow over time.

Both water and oil-based polyurethane products are readily available, offer similar protection, and come in a variety of finishes from glossy to matte. Polyurethane sealers don't penetrate the surface of the floors, but rather sit on top.

As with staining, ventilate the room and wear a mask if using a high VOC sealer, and put on proper foot wear. Working on a freshly vacuumed floor, apply the poly with a roller, using a paintbrush to get at the edges of the room. Just like with staining, work with the grain in two-foot sections, and plan your exit.

Polyurethane sealers require a few coats and buffing in between with either a machine or steel wool. You want to let them dry completely, but they can usually be done within a few hours of each other, depending on the product.

The more coats you apply, the more protection you will get, but there's no need to overdo it, either. Once you've done all of the required coats, allow the sealer to fully dry for at least 24 hours before walking on the floor, and wait three days before moving rugs and furniture back into the room.

Wood Floor Finishing Options

There are a few other finishing options you can use to seal your hardwood floors instead of polyurethane-based sealers. While polyurethane are the most popular and durable sealers, there are other options depending on the look and finish you want.

Wax was the go-to for hardwood floors before polyurethane finishes came on the market, and is making a bit of a comeback. Low in VOC's, wax is not glossy and achieves a nice, natural finish which can work well in older or historic homes.

It's harder to apply since it needs to be buffed into the wood by hand, but the upside is any scratches can simply be rebuffed and waxed as needed.

Shellac is another natural, low VOC product that dries quickly. Similar to wax, it isn't as durable as polyurethane, but can be re-applied as needed. Shellac has very good blocking ability, meaning it can prevent floors from absorbing smoke odor or pet urine, but it leaves an orange tint to the floors.

Tung oil is a popular kind of penetrating oil that offers another kind of sealing for wood floors where you want a more natural finish that seeps into the wood, rather than sitting on top.

Tung oil is a sustainable, low-shine product that's easy to apply, but won't offer the same durability as polyurethane, and needs to be re-applied every couple of years.

The finishing you choose will depend on the type of wood floors you have, but most jobs will use water-based polyurethane to achieve the typical "new floor" look that most homeowners want.

The most important part of finishing, however, is the preparation of the floors to take whatever stain and sealer you decide on.

Doing the job yourself can save you thousands of dollars depending on the square footage, but if you do decide to DIY this task, don't skip on any of the steps.

Refinishing your hardwood floors is not a job to take lightly, but if you do it right, your floors will look beautiful for years to come, and the investment will be well worth it.