How to Refinish Hardwood Flooring

hardwood floors being refinished

BanksPhotos / Getty Images

Refinishing a hardwood floor is a great way to revitalize the look of a room without having to go to the trouble and expense of installing brand-new flooring. The process involves removing the top layer of the covering material using a sander, which digs down past any scratches, stains, or imperfections that might exist, leaving you with a fresh surface to be stained, painted, or treated with whatever protective coating you prefer.

DIY vs Hiring a Professional

A professional will charge $3 to $5 per square foot to refinish a hardwood floor depending on the size of the job and the nature of the space and the material. The process will generally require about one week with cleanup.

If you perform the work yourself, then you will have to rent a walk-behind, solid-wood sanding machine as well as hand sanding tools, which will cost roughly $200 per day. Mistakes can also be made, which can irreparably damage the wood flooring surface, requiring costly repairs or a complete reinstallation.

The first step is to completely clean the surface of the floor. It should be swept or vacuumed to thoroughly remove any dust or debris that may be present. A slightly damp mopping, preferably by hand with a cloth rag, may also be useful to get rid of loose particles.

To begin the process of removing the damaged surface layer, use a large walk-behind sander, which can be pushed over the floor using a slow, even pace, to gently grind the wood down to a level that is below any finish treatments or damage. These machines are large ​and difficult to direct, and it is very important that you employ them in an even motion so that you do not get uneven surfaces, dips, or rises in the installation. The attached vacuum should suck up most of the dust that is generated.

Note: It is often a good idea to practice this process in an out-of-the-way area of the room, so you can get the hang of handling the machine.

Large machines will not be able to fit in corners or small spaces, so small hand grinders will be necessary to refinish these areas. While much lighter and easier to maneuver, these can be tricky as you have more control and can make more mistakes. Again, try to practice in areas that will not be highly visible in the finished space, so you can get used to this equipment.

Important Note: Hardwood flooring is often coated in chemical protective layers, which will be removed during the refinishing process. In older houses, these may contain harmful chemicals. Make sure that the environment is properly ventilated before you begin, and wear protective breathing gear and goggles to protect yourself throughout the entire process.

Once you have completed sanding the floor using power tools, you can work on any areas that remain using medium-grade sandpaper. This can also help to smooth out any rough patches that may have occurred during the process. If gouges are present, they can be filled using wood putty, which should be left to dry for at least 24 hours and then sanded with soft-grade sandpaper.

Cleaning the Dust

The vacuum attachments included in most power sanders will suck up the majority of the sawdust generated by the refinishing process. However, it is still important to sweep and / or vacuum the room thoroughly before proceeding.

Afterward, a tack cloth, which is much like a cheese cloth, can be dampened slightly and run along the floors and walls. Don’t let any water pool, and avoid inundating the wood with liquid. If necessary use several of these so that you can get every speck of debris clear before you move on to the next step.

Refinishing Treatments

  • Stain: This is an optional process that involves brushing a coat or two of a liquid material onto the wood, which will slightly change the color of the material, enhancing it and bringing out the natural features of the surface. There are a number of stains available ranging from dark browns and cherry reds up to golden hues.
  • Paint: In some cases, you may choose to paint your refinished hardwood flooring. This will completely remove the look of the wood, replacing it with whatever color that you choose.

Protective Treatments

Once the wood is sanded down it will be completely vulnerable to stains, damage, gouges, and scratches. That means that you need to apply a treatment that can help to protect it from further damage, so you can maintain the brand-new look of the surface for as long as possible. Some products can also enhance the appearance of the flooring itself.

  • Polyurethane: This is the best and most widely used protective coating. A clear almost plastic like substance, it is applied with a standard paint brush and is available in a variety of finishes from matte to glossy. Its purpose is to create a clear, protective layer over the top of the wood, which is resistant to liquids, stains, and scratching damage. Note: Polyurethane is a toxic substance and should only be applied in well-ventilated areas with the proper eye, hand, and breathing equipment. It will also require at least 24 hours to fully dry before the floor can be used again.
  • Varnish: This is similar to polyurethane, except that it has a more dramatic effect on the wood, darkening it noticeably. The advantage of this substance is that it is less thick, so spot repairs can be more easily made when future damage occurs.
  • Sealer: This is a thin, protective liquid that goes over hardwood, both seeping into the pores of the material and creating a clear surface coating over its top. It has very little effect on the look of the floor, but it also provides the least protection and may need to be reapplied every 6-12 months depending on traffic use.
  • Protective Finish Note: All of these substances should be applied according to the manufacturer's instructions and need to be brushed on in very thin, even lines. Allowing finish to bubble, pool, or sit in standing areas can cause permanent damage to the material.
    Make sure that whatever you use is applied in a thin, even coat, with no puddles or drips to affect the finished look. If necessary, these finishes can be sanded down then reapplied in areas to create a matched appearance.
    Often several coats will be used to enhance the changing effect and the protective benefits of the treatment. Follow all manufacturer instructions about drying time and the maximum number of recommended applications.