Sanding your hardwood floor with an upright sander is an essential step in the DIY refinishing process. Image source: Home Depot
Hardwood is a charming and low-maintenance flooring material, though wood floors can lose their luster over time and require refinishing every few years. If your hardwood floors are starting to show their age, it might be time to rent an upright sander and pick up some polyurethane.
Of course, if you want to leave this moderately difficult job to professionals instead of tackling it yourself, that’s an option. It’s fairly expensive to professionally refinish hardwood flooring, but your floors are some of the most important elements of your home, so you’d be justified in splurging on their care.
Whether you’re leaning towards hiring a contractor or going DIY on your floorboards, we can help. In this guide, we’ll break down the pros and cons of each option, point you to some professionals in your area, and provide step-by-step instructions for completing this home improvement project on your own.
- Hiring professionals to refinish your floors can cost thousands of dollars while doing it yourself typically only costs a few hundred for materials and machinery rentals.
- Not all floors can be refinished. If your floor is made of laminate, you can’t refinish it. If your floor is made of veneers, then you may be able to refinish it, though it isn’t always possible. If your floor is all-natural hardwood, you can likely refinish it, though old floors are sometimes worn too thin to withstand the process.
- To refinish your floor yourself, you’ll need to go to the hardware store to pick up an upright sander, a can or two of polyurethane sealer, a roller brush, some safety equipment, and a few other supplies.
- DIY floor refinishing is a multi-step process that can take days of hard work to complete. And if you don’t follow the directions on your equipment and materials, it can turn disastrous. As such, the job is best left to professional contractors, though DIYers successfully pull it off all the time.
On this page
- How much does it cost to refinish hardwood floors?
- Why you should hire professionals to refinish your floors
- Not all wood floors can be refinished
- How to refinish hardwood floors yourself
- Is it time to refinish your hardwood floors?
How much does it cost to refinish hardwood floors?
You should expect to pay about $5 per square foot to professionally refinish a hardwood floor. Most homeowners pay about $1,200 to get a single room’s floor sanded and refinished, though average prices range from $800 to $3,100. These prices vary so drastically because multiple factors influence the price of professional refinishing.
These factors include the type of wood your floor is made of, what type of finish your contractor seals the floor with, and the size of your floor. To get a complete understanding of how these factors affect your final price, read our hardwood floor refinishing cost guide.
Refinishing your floor yourself is much cheaper, but it’s still more expensive than you may think. Between renting sanding equipment from a hardware store, buying a few cans of polyurethane and stain, and purchasing applicator pads, DIYers still spend hundreds of dollars when they refinish their floors.
Why you should hire professionals to refinish your floors
While refinishing your floors with your own two hands is undeniably cheaper, we still recommend hiring a professional for the job if you can afford to.
Between buffing, staining, and applying finish, there’s a lot that can go wrong when you refinish a floor. For example, if you don’t know how to properly use a random orbital sander, you can badly gouge your floorboards – and this is just one possibility. This job requires using a lot of equipment you’re probably unfamiliar with.
If you do happen to inflict significant damage to your flooring by improperly using the appliances or tools required, you could end up paying a professional to refinish the floor anyway to amend your handiwork. If the damage is beyond repair, you might even need to fully replace your hardwood, a job that can cost close to $8,000.
Additionally, floor finishes and wood stains are made from powerful, toxic chemicals that need to be properly handled to prevent hideous splotches and—in extreme cases—making indoor air hazardous to breathe.
All things considered, it’s safer for you and your floors to simply hire professionals. That said, floor refinishing isn’t the most intense DIY project, and plenty of people successfully pull it off their first time. If you decide to accept the risks and pursue the DIY route, read on!
Not all wood floors can be refinished
A floor may look like it’s made of solid hardwood, but that doesn’t necessarily mean it is. Two types of flooring are made to mimic the look of hardwood: laminate flooring and engineered wood flooring. Neither of these imitators is ideal for refinishing, though laminate is much worse.
Laminate floorboards are made using synthetic resins, not real wood, but they can be colored and sculpted to imitate the colors and wood grains of various trees.
One of the easiest ways to tell if your flooring is made of laminate is to carefully inspect the grain pattern. If the pattern repeats every so often, the flooring is laminate. If the pattern on every piece is completely unique, then it’s genuine wood. Another way to tell is to touch the floor. If it feels like a vinyl record or a plastic dinner plate, it’s probably laminate.
Unfortunately, if your flooring is laminate, you’re out of luck. Because it’s made from nonporous synthetics instead of organic wood fibers, laminate is impossible to refinish, and sanding it down will only destroy it.
Engineered hardwood flooring
With engineered floorboards, your situation is probably less dire. Engineered floors are made with plywood plank interiors and veneers of authentic hardwood. Because of this construction, these floors are sometimes called “veneer floors.” Depending on the thickness of the veneer, you may be able to refinish an engineered hardwood floor.
If you’re unsure if your floorboards are authentic or engineered hardwood, you can check by pulling up a floor vent cover in the room and looking at a plank’s exposed cross-section. Alternatively, you can also temporarily remove the saddle at the base of a doorway to reveal the sides of your floorboards. If each board is layered like a cake or a sandwich, your floor is made from engineered hardwood. If it’s one solid piece, it’s authentic wood through and through.
If your flooring is engineered, this method can also tell you how thick the veneer is. Measure the top layer of a floorboard. If it’s around three millimeters thick, you can usually sand it down enough to refinish it. If it’s significantly thinner than this, though, sanding could bare the unsightly plywood cores of your floorboards, so you shouldn’t attempt a refinish. A pro may be able to tackle it for you, though.
Authentic hardwood floorings
Even if your floor is made from natural hardwood, you should still check its thickness before sanding. This is especially a concern in older homes with original flooring. You can check your flooring’s thickness using the vent or doorway saddle tricks described above or by inserting a credit card into a crack in your floorboards.
If your flooring is less than a quarter inch thick, you should probably avoid sanding it or it could disintegrate beneath your sander. If you discover that it’s at least a quarter-inch thick, though, you’re ready to get started.
How to refinish hardwood floors yourself
Step 1: Gather your equipment and materials
Unfortunately, you probably can’t handle this job with whatever home improvement tools and materials you have lying around in your garage. As such, your first step is to buy and rent all of the stuff you’ll need for sanding, staining, and refinishing your floors. Here’s a complete list of everything the job will require:
- Protective eyeglasses and earplugs
- Heavy-duty gloves
- Respirators and dust masks
- Protective plastic sheets
- Painter’s tape
- An upright floor sander (rental)
- A handheld sander
- A shop vacuum
- A pry bar
- A roller brush
- A wide paintbrush
- A hammer
- Tack cloth
- Clean but disposable rags or sponges
- Medium-grit sandpaper and sanding belts
- Fine-grit sandpaper and sanding belts
- Wood stain
- Polyurethane wood finish
How to pick your floor sanders
When you go to the hardware store to pick up your upright sander, you’ll be presented with two options: drum sanders and orbital sanders. The main difference between the two is power.
Drum sanders are much stronger than orbital sanders, so they’re better for heavy-duty sanding jobs. If your floor is heavily scraped and scratched, a drum sander can help you buff out the damage. It’ll have to eat away more of your floor to do so, though.
Orbital sanders, on the other hand, are less powerful, so they’re only really good for light sanding jobs. Luckily, if your floors aren’t banged up too bad and just need another coat of varnish, then an orbital sander will usually do the trick. Additionally, an orbital sander’s decreased power makes it a better option if you’re DIYing a floor sanding for the first time.
You’ll also need a handheld edge sander for sanding down corners and spaces under cabinetry overhangs where your upright sander can’t reach. In theory, you can actually sand your whole floor with a handheld sander like this, and while it will be much cheaper, it will take a lot more time. Imagine mowing your lawn with a weed whacker instead of a lawnmower.
Whatever upright and handheld sanders you pick, make sure you pick sanding belts and sandpaper that are made to fit them. When in doubt, ask a clerk to help you find the right stuff.
Picking your polyurethane finish
There are two types of polyurethane floor finishes: oil-based and water-based. To choose the right one, you’ll need to assess how much traffic the floor gets, how lustrous you want it to be, how soon you need to use the room again, how much you want to spend, and how nasty you want the chemicals you’re handling to be.
Water-based polyurethane sealers dry quicker than oil-based options, allowing you to apply multiple coats in a single day and start walking on the refinished floor sooner. They also release fewer volatile organic compounds (VOCs) than oil-based polyurethane. VOCs are toxic chemicals that can cause several serious health problems.
There are three main downsides of water-based options. They typically don’t last as long in heavily-trafficked rooms, they’re more expensive, and they don’t give wood as rich a look as oil-based sealers.
Oil-based polyurethane, on the other hand, takes much longer to dry and can extend your refinishing project by several days. It also releases much heavier dosages of VOCs into your air while it dries, making it more dangerous if you don’t properly ventilate the area.
On the plus side, oil-based polyurethane tends to be more affordable, it’s a bit more durable, and it gives the wood a healthy glow that homeowners love.
No matter which option you go with, you can still get your preferred glossiness. Both types of polyurethane come in high-gloss, semi-gloss, and satin options.
Step 2: Prepare the room and clean the floor
Once you’ve gathered all the materials you’ll need to sand and refinish your floor, it’s time to prepare the room. First, you should remove all your furniture and rugs. Then, use your pry bar and hammer to carefully pry out your baseboards. You’ll need them out of the way to sufficiently sand and refinish the edges of the room. Just make sure you remove them slowly or you could damage them.
Next, thoroughly sweep and mop your floor. Any hair, debris, or dust particles that ride out the cleaning and sanding process will be sealed into your floor, eternally giving it a grimy look and texture, so you may want to go over the floor two or three times with a mop.
When you’re satisfied with the cleanliness of your floor, it’s time to put your plastic sheets up. Use painter’s tape to adhere the sheets over your vents, doorways, cabinets, and walls. This will protect everything from sawdust and splatters.
With all of this done, it’s finally time to start sanding.
Step 3: Sand the floor to remove the old finish
Put on your protective glasses, respirator, gloves, and earplugs, and then put a medium-grit sanding belt onto your upright sander. Then—while following the operating instructions provided in the machine’s manual—turn the sander on and start pushing it across your floor, starting in one corner of the room.
You want to steer the sander in the same direction your wood grain points, passing over your floorboards parallel to the cracks between them. And, like with a lawnmower, you’ll want to go back and forth across the floor in straight lines several times.
When you complete one pass, tilt your machine backward to lift the sanding belt off the floor, turn around, and make your way back in the direction you just came. With each pass, you want to slightly overlap the floor sanded during the previous pass to ensure complete coverage.
Pro tip: don’t ever steer the machine directly up to the walls or you could scuff them. This will leave your edges and corners unsanded, but you’ll get to those later.
It’s also important to avoid lingering in any one spot for too long. Your sander will be chewing into your floor constantly, so even a brief pause can result in a slight but permanent divot in your floorboards. You should be moving briskly at all times when the machine is running.
Once you’ve sanded the entire floor once, it’s time to break out the handheld edger. Fit it with medium-grit sandpaper, then get down on your knees and sand the edges and corners you couldn’t hit with the upright sander. This is also how you should sand the flooring under any cabinets or radiators.
After you’ve sanded the entire floor with the medium-grit sandpaper, use your shop vacuum to remove all the sawdust. There will probably be a surprising amount of it hanging around.
Once you’ve cleaned out all the sawdust you can get, it’s time to sand the floor again, this time with fine-grit sandpaper. The first sanding will have removed most of the old finish, but it will have left your floor a little rough. The second sanding is meant to smooth everything back out. Install a fine-grit belt onto your upright sander this time and pass over the entire floor again like you did the first time.
The second sanding can probably go a little quicker than the first, but make sure you’re no less thorough. Once you’ve finished your second sanding with the upright sander, put fine-grit sandpaper onto your handheld sander and hit the corners once again.
Once you’ve finished, roll the shop vac back out and remove all the new sawdust. This time, you should be especially meticulous and avoid leaving any sawdust that could get sealed into your wood. After vacuuming, go over the entire floor with a tack cloth to wipe up any particles the vacuum missed.
Step 4: Restain your floor
With the sanding finished, you’re ready to stain your floors if you’re choosing to do so. This is only necessary if you want to change the color of your flooring. Be aware that sanding often lightens a floor, so your floorboards won’t be the same color as they were before. If you like the post-sanding color of your wood, though, you can skip this step.
Open your windows and doors to ventilate the space, put on your respirator if you took it off, and prepare your can of stain however the label recommends. Then, using a rag, applicator pad, or sponge, apply your stain evenly across the hardwood.
As with the sanding, you want to wipe in the direction of the wood grain. Wiping perpendicular to the grain can result in ugly streaks. You should also avoid laying the stain too thick in any one spot or it will become darker than the rest of the floor. You’re going for a nice, even coat throughout the room.
Once you’ve stained the entire floor, let it dry for as long as the label on the can recommends. Drying time varies between stains, but you usually have to let the stain dry overnight. If your floor isn’t the desired color after the first staining, you may need to apply a second coat once the first one is dry.
When your floor has reached the shade you want and the stain has completely dried, it’s time to move on.
Step 5: Apply your finish and let it dry
With your respirator on, your windows open, and your can of polyurethane mixed according to the directions laid out on the label, it’s finally time for the main event: applying the finish.
The technique is basically the same as if you were painting a wall. Pour some of the finish into a paint tray for easy dipping, then start applying it to your floorboards with a roller brush.
Roll the brush in the same direction as your wood grain to avoid streaks. Once you’ve hit every spot you can with your roller brush, you’ll probably need to use a paintbrush to touch up the edges and corners. Roller brushes often can’t reach into these angular spaces.
Once you’ve laid down your first coat, let it dry according to the drying instructions on your polyurethane can. This might only take a few hours, but it could take all day depending on the finish you purchased. Then, apply subsequent coats by repeating the whole process as many times as the label recommends.
Once you’ve applied your final coat of finish, you should give the floor about 24 hours of drying time before you start walking on it again and at least three days before you put your furniture back into the room.
Step 6: Put the room back together
Once the finish has dried and cured, it’s time to make the room usable again. Take down your plastic sheeting, replace all the moldings, saddles, and vent covers you removed during the process, bring all the furniture back into the room, and lay out your rugs. You can now use the room as normal. Be aware, though, that you should keep the room well-ventilated for as long as the polyurethane odor lingers.
Is it time to refinish your hardwood floors?
While it may seem intense, refinishing a hardwood floor is a relatively straightforward project that you can usually pull off by following the directions on your equipment and materials. It’s always safer and more stress-free to just hire professionals, though. However you choose to get the job done, good luck and enjoy your floor’s new finish!