How to Refinish a Hardwood Floor

Hardwood Floors

Many older buildings, especially those built prior to the 1960s, very likely have hardwood floors under that ugly stained excuse of a carpet. Originally, hardwood floors were strictly structural. The planking that made up the flooring ran at right angles to the underlying joists. This made for a very strong stable structure.

With buildings prior to the 1960s this was indeed the case, but they are still very pretty to look at and considerably cleaner and easier to clean than any carpet.

Cleaning and Health Benefits
Cleaning a hardwood floor is much easier and faster than cleaning a carpeted area; especially if the object is to get a thorough cleaning.  Even with a high quality vacuum cleaner carpet will trap dirt. Worse, it also traps allergens, dust and germs.

This is not as much of a problem with hardwood floors. Dust is easy to get up with the proper tools (a dust mop) and germs can be banished with a regular mopping with wood floor soap.

It looks much nicer too.

Still want a carpet? Use a throw rug.

No Carpet

This hub assumes that there was no carpet to begin with or that it's already been removed. The hub will assume that there remains some staples, nails, glue, and carpet strips.

The first problem is the carpet strips. These are narrow wooden (typically) strips with bent nail heads sticking out in the wrong direction. They are designed to grab the carpet from the underside so that the installer can pull that carpet taught and expect it to stay there; gripped in place by the aforementioned nails.

These strips are a pain frankly and they'll take a fair amount of time to get out. Expect to spend a day doing this with an averaged sized home (say 500~800 square feet). There are some tricks to removing them and I'll share them below.

Pry (or Crow) bar
Pry (or Crow) bar
Claw Hammer
Claw Hammer

Removing Carpet Strips

Large Pry/Scraper
A good hardwood floor is exactly that, hard wood. Despite appearances you really don't have to worry about scraping or gouging it unless you get just a little too radical. After all, you are going to sand the floor if for no other reason than to get it flat and level again. For that reason I use a large, long-handled scraper to remove the strips.

Aim the business end of the scraper at the strip closest to where the nail is and slam it under the strip. With careful aim you won't gouge or scrape the floor and you'll be able to drive the edge all the way under the nail. Now that it's there push down on the handle to pry up the nail. With a touch of practice you can make this eight hour job much easier on yourself and suffer much less back pain and sweat.

Pry Bar/Claw Hammer
Of course there will be areas where there's not enough room to use this scraper and for that you'll want to use a two foot pry bar. A good pry bar should have a hooked section on one end, a straighter area on the other, and a nail removal "oval" near the straighter end. The one pictured is not the ideal bar, but it's close.

You can also use a carpenter's claw hammer. This is a hammer with a claw on the opposite end with a distinctive angle on the claw.

If you are worried about scuffing the floor pass on the floor scraper and stick to the pry bar. Use some scrap wood strips (thin ones are best) between the tool and the floor. This way the scrap wood will take the punishment, not your floor.

Removing Glue

Often contractors will use glue to fasten the foam or felt under the carpet to the floor. Assuming you've already removed the carpet you still have to get rid of the glue.

First try the scraper above. This should remove at least the surface glue to some extent.

If it's been there a while even a scraper might not work, for this situation us dry ice. You should be able to find a supplier with a few phone calls. Be sure to take a cheap foam cooler with you and some good heavy gloves. Leather or new faux-leather crew gloves should work well as long as you don't hold the ice too long.

Once back on site, place the dry ice on the glue for about a minute and then use a hand sharp paint scraper to get it up. The cold dry ice will make this job much easier than trying to get it up at room temperature.

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Slip Joint Pliers with flush nose.These pliers are NOT SUITABLE!
Slip Joint Pliers with flush nose.
Slip Joint Pliers with flush nose.
These pliers are NOT SUITABLE!
These pliers are NOT SUITABLE!

Removing Staples

Sometimes contractors will use staples instead of glue to hold down the carpet pad. If this is the case simply remove them with a good set of pliers. The pliers should be well crafted to the point that when the jaws are closed there are no gaps between the two sides and the flush end of the pliers should be even on both sides. e.g. when closed the blunt end of the pliers should form one solid level surface.

To remove the staple grab it with the pliers, grip the pliers tightly and pull straight up.

You can find all of them, which can be a daunting task since they are so small, by wearing a pair of crew gloves and passing your hand over the floor for the entire surface. A staple will be obvious.

Removing Stains

Stains are a real problem. They can be shallow or deep. The problem, of course, is you really have no idea how deep a stain is until you start sanding the floor to remove the old finish.

There are a number of products out there now that do a halfway decent job of what used to be impossible. They are costly though and designed to deal with a particular kind of stain. Try the methods below before spending $20.00 or so dollars on a product that may not do the job.

First, you should try a good wood cleaner. Most makers of stain and urethane also make wood floor cleaners. This way you can tell genuine stains from just plain dirt.

Identify the Stain
If you can, identify what made the stain. There are different treatment options for different types of stain. The good news here is they are all cheap "home-remedy" solutions. These are, by stain type:

  • Water Marks: Try rubbing the area with vegetable oil and then wipe dry.
  • White Marks: Make a paste of ash (from your grill) and vegetable oil. Rub this on the mark until it disappears then wipe dry.
  • Alcohol or Milk: Rub the stain with rottenstone (a very find powder from rock; also known as tripoli), followed by a damp cloth then dry cloth rubdown.
  • Light burns: Cigarette burns for example. Rub with rottenstone and/or linseed oil, along the grain, until the burn disappears. Linseed oil will blend into the wood and harden.
  • Mildew: Dry the area as much as possible and then wash the area with washing soda or trisodium phosphate (a common laundry detergent additive). Once clean, dry immediately.If the floor is still wet, the reason for the mildew, dry with a portable heater or infrared heat lamp at a safe distance...about two to three feet.
  • Other Stains: Try a rubdown with mineral spirits on a rag. Do not pour mineral spirits directly on the floor. Apply to a rag and then the rag to the stain. Whether this removes the stain or not follow up with a clean dry rag to remove the mineral spirits. Mineral spirits will also evaporate over time.

If none of these methods work the stain is likely very deep and you may consider replacing the offending plank. This could be a very expensive proposition. Knot free wood is very hard to find these days, especially in the classic flooring material, oak. Of course, you'll also have to determine what type of wood you are replacing to get the right match.

Wood Species
There are many varieties (species) out there and they've been used for decades if not centuries. These include, in order of current popularity, oak, pine, walnut, ash, beech, birch, cherry, hickory, chestnut, maple, and pecan. Oak was by far the most popular in the past with a nice hard pine such as "white pine" and "Long Leaf Heart" pine second. The most popular hardwood today is not even wood; it's a type of grass called bamboo. Bamboo is perhaps the best material for flooring these days. It grows fast, is very hard, resists stains and wears very well. I also personally like the way it looks.

As to what type of plank you purchase, maybe a knot here or there won't matter to you, but if you are a purist spring for the more expensive blemish free wooden plank. They are easy enough to spot. After all this is where a branch grew of out of the trunk of the tree. It look very much like a round spot or oval and it's usually darker than the surrounding wood.

Replacement Planking

If you do opt to replace a few planks of wood on your floor be sure to determine the species (above) before going down to the lumberyard. The easiest way to do this, of course, is to remove the offending plank and take it with you.

Typically planking comes in particular widths, the most common of which is 2 and 1/4 inches. Early American flooring came in various widths per board ranging from a narrow three inches to a wide six inches. It wasn't until Victorian times and the advent of the machine age that board came in a standard width for flooring.

Getting the width of the replacement plank or strip is as important as getting the species correct.

Note a strip is any board under three inches. A plank is any board at or over three inches.

If you live in an exceptionally wet or dry environment you may want your plank or strip to "acclimatize" before installation. This may take a week or two, but what it will do is allow your plank or strip to have the same moisture content as the surrounding floor. This will prevent shrinkage or expansion after installation.

Check with a hygrometer. Test the surrounding wood and then the plank or strip. if they are withing 2% or 3% of each other in water content it's safe to install. Anything bigger difference and you should let the plank or strip sit in the same room until its moisture content is the same as the floor.

Burns

If you can't remove the burn described above (cigarette burn example) you are taking a gamble. With oak or ash it's very hard to tell just how deep a burn goes. You can certainly try sanding it away with the example below, but you might want to be prepared to replace the plank.

If sanding away a burn you'll need to sand a much larger area than just the burned spot to avoid making a depression in the flooring. Remember, one of your objectives is to end up with a flat level floor that your furniture won't end up not sitting on properly.

Replacing a board after sanding is also problematic. If you replace the offending plank after sanding the entire floor you'll now have a slat that's slightly thicker than the rest of the floor, so bear this in mind as your are trying to remove the burn or other stain.

Paint

There are all sorts of solvents for paint these days, but they come with their own built-in problems. If you do use a solvent to remove paint you'll also have to remove any traces of the solvent. This alone could cause a delay in finishing your floor as you wait for the solvent remover to dry.

Use Heat and a Scraper
The best way to remove paint, particularly latex, is with a heat gun and a paint scraper. Of course, if you've never done it before it's going to take a bit of practice. No, you aren't likely to set the floor on fire, but applying too much heat or heat for too long will simply waste your time and cause the job to take longer.

A good heat gun only takes a few seconds to get the offending paint soft enough to remove and then a good sharp-edged scraper will make short work of the paint; no matter how long it's been there.

I suggest practicing with both on an area of the floor where mistakes aren't going to haunt you by being glaringly visible every time you look down.

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Drum SanderLarge Orbital SanderEdge SanderDetail/Corner Sander
Drum Sander
Drum Sander
Large Orbital Sander
Large Orbital Sander
Edge Sander
Edge Sander
Detail/Corner Sander
Detail/Corner Sander

Sanding

The amount of wood (due to burns/stains) and or surface wax/varnish/sealer you have to remove is the determining factor to a sanding machine. Unless your floor is relatively pristine you do not want to hand sand it, that will simply take too long.

There are four types of sanders for various amounts of removal. The "big gun" is the drum sander. This is the machine to use for removing large amounts of wood and leveling the floor.

The large orbital is better for light removal or simple surface prep. However, you can use this machine if the drum sander just seems like too much to handle. Just use a lower number (36 or so) sandpaper.

The edge sander is for areas that the drum or orbital won't reach. Chance are you'll want to use this sander regardless of which of the other two you do use. The professional edge sander will cover more area than a workshop sander and make the job faster and easier. This will not reach into corners very well though.

Finally, the corner sander is for exactly that. The areas of the floor where two walls come together at a right angle. This is the only sander you are likely to buy rather than rent. The good news is you can get a very high quality sander that fits neatly into corners for $40 or less.

Large Drum Sander
Rapid removal and large area.

This is a sander specifically designed for resurfacing hardwood floors. It's large machine which typically takes a large sandpaper belt in a continuous loop. The machine is designed as a "walk-behind" tool. They can be rented at most major hardware chains at reasonable rates. The upside to using a sander like this is you "check-out" the sand-paper grades you want to use along with the machine and then pay for the belts you've actually used (and the time you've had the machine) when you return it. Most major chains will pro-rate the charges by the hour. Be sure to ask.

It has it's draw-backs. It will take a large amount of surface off in a very short time. For this reason it's a risky tool to use as it's very easy to gouge the floor and leave groves in the wood.

With this type of tool technique is virtually everything. You should never have the machine running at a stand-still. Whenever this type of sander is running it should also be in motion. You should also sand in the direction of the grain of the wood.

As you sand with this type of machine be sure to push it forward at a constant rate. Initially, sand a small area with it, use a shop-vacuum to remove the saw-dust, and then take a look at the effect. If too much is removed quicken your pace; too little slow down a bit.

If you do gouge the wood go over it with the sander at a 45° angle to the gouge keeping the machine in motion at all times. When removing a gouge move the machine at a faster rate than you would during normal sanding. This will take some time as you will want to remove the gouge in small steps, remove the dust with a vacuum,

Large Orbital Sander
Moderate removal and large area.

This sander is just an extra large version of an orbital sander. It's benefit is that it can help you level a floor without taking too much wood away. It will certainly remove varnish and shallow stains and burns. For stains and burns that run deeper the drum sander may be the better choice.

As with the drum sander, expendables such as sandpaper, scouring pads, and the like are picked up at the time of rental and charged for upon the machine's return.

Unlike the drum sander gouges are much less likely. It's also an easier machine to operate as the orbital action cause the machine to "glide" over the surface of the wood. With this type of tool your technique is not as important, but you still want to sand in the direction of the grain of the wood and you always want the machine moving as it's running.

Edge Sander
Used to sand to the edge of the wall.

Neither the drum nor large orbital sander will allow you to get all the way up to the intersection of the wall and floor. This is what the edge sander is for. Like the orbital, technique is not as important, but you do want to sand in the direction of the grain and keep the sander moving if it's running.

Corner/Detail Sander
Used to get into the corners where two walls come together at a ninety degree angle.

This is the sander you are most likely to purchase and least likely to rent. There are a number of models available now and they will all reach right into the apex of the corner. The best are lightweight yet powerful and are designed to sand into the smallest crevice. They also fit neatly into the hand.

Notes on Sanders
The rented sanders (drum, large orbital, edge) have some particulars about them that you, the renter, should be aware of.

The drum sander weighs about 110 pounds. If you are sanding on a second (or higher) floor or need to haul it up a step or two you may need a helper for assistance. The drum will sand a very large area before the sand-paper needs to be replaced. Also, changing the paper roll is relatively easy. You will also want to clean the machine completely before returning it. Most rental outlets will charge a cleaning fee if you return a dirty machine.

The orbital sander weighs about 120 pounds. As with the drum above you'll need a helper if you are sanding above the ground floor just to lift it. The paper is quite large (roughly two by three feet) and you'll be able to sand quite a large area before having to replace the paper. Paper replacement is very easy. Cleaning this machine will also help you avoid a cleaning fee upon return.

Edge sanders go through paper slightly faster than the two above. It's also a heavy machine but nowhere near even 25 pounds. Still it's a good rental option if you want to get the floor ready for stain or be able to stain and seal in short order.

Sandpaper
Regardless of sander type you'll want to start with a very course grit (20 or 36) sandpaper and work up to finer paper. Remember that the lower the number of the paper the courser the grit and the more wood will be removed. The higher the number the finer the grit and the less wood will be removed.

Start with 36 grit for normal wear and tear sanding or with 20 grit for deep stains and or burns. Once you've done the entire floor to the same depth move up to a higher grit ending with 80 or 100 just before staining. This may require you to make three to six passes with higher grits each or every other pass.

You should always sand the entire floor the same amount regardless of what imperfection you are trying to remove. Sanding is always about more than just preparing the floor for a new finish. It's also about getting the floor smooth and level again.

Sanding Direction
Unless you are sanding the edges where the wall and floor come together, you always want to sand in the direction of the grain or plank. The only exception to this is if you create a gouge with the drum sander. In that case sand the gouge at a 45° angle to the planking.

Cleaning up the Dust

Vacuum
Once you've sanded and are sure you have a level floor and all the imperfections have been sanded out you want to clean.

The best process I've found is to vacuum with a squeegee attachment and shop-vac. A good shop vacuum will allow you to clean large areas of the floor quickly. Using the squeegee attachment you can vacuum large areas of the floor. You can also detach the squeegee and extra hosing to get into the corners where the dust will accumulate.

Mop
Mopping with plain water is the next step. You don't want to use a soap solution or any other type of cleaner as the point here is to leave the floor in it's unfinished state once through. In other words by using clean pure water you do not add impurities from soap or oil (from an oil soap). Later, you'll be using mineral spirits for a final cleaning anyway so why complicate matters.

Simply use clear cool water and rinse the mop quite head often.

You'll also want to let the water dry from the mopping so this should occur four to six hours before you apply the stain and/or finish.

Mopping will give you a good idea of what the finished floor will look like. The moisture from the mopping will mimic what the finished floor should look like.

If you see imperfections as you mop, make a note of where they are and correct them by sanding again if necessary. Once the floor is sealed it will be very hard to correct those imperfections; though not impossible. Small imperfections tend to really stand out once a finish is applied.

Vacuum Again
Finally, vacuum one more time.

Wood Stain

OPTIONAL! YOU DON'T HAVE TO STAIN YOUR FLOOR.

Choose a stain that will complement your décor. Perhaps the most popular is Walnut and this particular color comes in at least three shades; light, medium, and dark.

Stains come in two basic formulations. Water-based and oil-based.

The water based stain isn't a true stain. Once applied, it sits on the surface of the wood and acts more like a paint than stain. Also, water-based stains tend to be brighter in color and less natural looking. The advantage to a water-based stain is very fast drying times. Two hours for drying is typical.

Oil based stains are much more natural looking, actually penetrate the wood and are much slower to dry; up to eight hours in fact.

Applying the Stain

As with sanding and cleaning, stains should be applied along the grain of the wood. My favored method is to apply the stain with a three inch (or wider) brush and then, after a minute or two, a rubdown (with the grain of course) with a clean dry rag.

The rag and brush should last, without replacement, for the entire surface of the floor.

Always follow the manufacturers recommendation on drying times for stains. This could be eight hours (if oil based) or longer.

This is not the time to rush your job!

Cleaning Prior to Sealing

Once you are sure the stain is dry go over the entire floor with mineral spirits. A quart of mineral spirits will clean 500 to 800 square feet of floor. Apply the spirits directly to a clean dry rag and rub into the floor in a circular followed by "with the grain" motion.

Mineral spirits will remove any residual stain sitting on the surface along with dust and other impurities that can become trapped in the sealer.

This is the final step before sealing the floor and you should do it whether or not you've applied a stain. Using mineral spirits as a cleaning agent will insure that the sealer you apply sticks to the floor without a chance of bubbling up or coming off. Mineral spirits will also evaporate leaving a clean, dry, impurity free floor.

Sealer or Finish

YOU SHOULD ALWAYS SEAL THE FLOOR.

Oil Seal
You can opt not to seal the floor with modern sealers though I highly recommend using them. Sealers are primary water based which means they dry fast, are easy to apply, and easy to clean up after.

Decades ago urethane was not available and the common method of sealing a floor was with oil. By using an oil seal you can then clean the floor with products designed specifically for wood floors. A quick google search of "floor oil" will result in a number of products designed specifically for this purpose. Tung oil is likely the most popular, but there are also formulations out there consisting of other types of oil such as linseed.

If you do use an oil sealer be sure to follow the manufacturers recommendation on drying times.

To apply the oil seal follow the manufacturer's recommendations, but typically you "paint it on" like you would the stain and then, after a few minutes, rub it in, with the grain of course, with a dry clean rag.

Urethane
This modern finish has some definite advantages. It's easy to apply, drys fast, and, depending on the gloss level you choose, can look highly polished or like an oiled finish. Best of all they are water-based for quick and easy clean-up with plain soap and water.

A semi-gloss will give you an oil-finish look. A gloss will give you a high luster.

As with an oil finish follow the manufacturer's recommendations on applying and drying times. prepare to leave the house or apartment for a full day once finished. Urethane sealers take two hours to dry to a tacky finish so another coat can be applied and up to three days for a hard scuff resistant finish.

Regardless of sealer be prepared to put down at least three coats for maximum protection. To provide the best protection for your flooring try applying heavier coats of sealer in high traffic areas such as thresholds, hallways, and paths that are certain to see high traffic.

Disclaimer

The author has not been compensated monetarily, with discounts or freebies for any products  mentioned in this article.

Google Adwords ads are randomly placed with this article, but the author has no control over ad content or direct contact with the companies paying for those ads. The author does stand to make a small profit from those ads regardless of his lack of control over those ads.

Though the author has not mentioned brand-names for equipment, those machines carried by the big "do it yourself" outlets are the brands recommended. They are high quality machines, made in America, and designed for decades of reliable use.


Carpet Removal

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Comments 6 comments

LiamBean profile image

LiamBean 6 years ago from Los Angeles, Calilfornia Author

Thanks billyasutindillon. I've linked your hub here.


billyaustindillon profile image

billyaustindillon 6 years ago

Very well done - I have a little hub on sanding :( and finishing - you cover it all here.


LiamBean profile image

LiamBean 6 years ago from Los Angeles, Calilfornia Author

Thanks John B!


John B Badd profile image

John B Badd 6 years ago from Saint Louis, MO

Very good hub, the information is detailed and well explained.


LiamBean profile image

LiamBean 6 years ago from Los Angeles, Calilfornia Author

Thanks 2besure!


2besure profile image

2besure 6 years ago from Charlotte, North Carolina

Very informative hub! Wood floors are to die for. They are warm, beautiful and easy to keep clean.

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