Refinishing a wood floor

Refinishing a wood floor

Written by Matt

How to refinish a wood floor?

If you choose to refinish a wood floor yourself rather than engage an experienced floor refinishing professional, you will need to understand the pros and cons of both options. Refinishing a wood floor yourself may reduce the overall cost of the project; however, the time, effort, equipment rental, and material costs will still be significant. It may not be worth it to end up with inferior results once you have completed your D.I.Y sanding and refinishing project. Either way, having the correct tools, equipment, and information is essential before deciding to do it yourself.

The process I use when refinishing a wood floor has developed through training and trial and error. In the early years, I worked for a few companies that taught me “their way” of refinishing wood floors. As the years went on and my experience with different finishes and wood floors expanded, technology also advanced. As a result, the process I now use to sand and refinish is faster, easier, and produces better results than those who “trained me” over two decades ago. While the floor sanding, floor polishing, and floor coating processes remain similar, the steps, techniques, and equipment I now use are significantly more advanced, as the results show.

1. Floor sanding

The first process of refinishing a wood floor is sanding off old coatings while flattening and smoothing the boards. Please note that floor resurfacing is a more involved process and may require punching nails, replacing boards, or removing old floor coverings. To remove old coatings, 2 pieces of machinery are required.

  1. A drum or belt sander is required for the main areas of the floor. Experienced professionals generally use a 220v, 8, 10, or 12-inch commercial belt sander instead of a drum sander. A drum sander tends to leave a “chatter” effect due to the paper join. “chatter” is a pattern of waves produced by inferior or unbalanced floor sanders and is almost impossible to remove during the following polishing stages. Belt sanders are fitted with a continuous belt, and when maintained and balanced, they eliminate “chatter.” Most rental machines are either drum or small, 110v domestic belt sanders. Drum and belt sanders are very powerful; even the tiny rental machines will destroy a floor if misused, unbalanced, or not maintained. Irreversible gouges, dents, and divots in wood floors are typical when using a drum or belt floor sander without adequate training. These machines can be hazardous in the wrong hands or without personal protective equipment.
  2. Floor edger machines are used around the floor’s perimeter and other areas too small for a belt sander to reach. Professional floor refinishing contractors will almost always begin their training using a floor edger as they are smaller, lighter, and generally more straightforward to use. Floor edgers are handheld rotary sanders fitted with various 8-inch floor sanding discs. Edgers are loud and powerful and must be correctly balanced before sanding. An incorrectly balanced or handled floor edger will produce the same problems as other larger floor sanders. The most common issues associated with edging are “gutters” and “swirl” marks that polishers will not remove. An experienced floor sander will smoothly sand to base and kick boards. I connect my edger to a commercial dust control vacuum fitted with a HEPA filter. Most rental machines are old, unbalanced, and produce large amounts of dust.

Creating a smooth floor

  • When used correctly, old finishes, surface scratches, dents, and gouges are removed from the floor with various course grit sanding belts ranging from 24-120grit. Commercial belt sanders also have a powerful impeller that effectively contains the dust created while sanding. Domestic rental sanders produce more significant amounts of dust when sanding a floor that has been previously coated. ALL the old coatings must be removed, which may take multiple sands. Not removing old coatings will result in a botched finish once sealers, stains, and new floor finishes are applied. These floor machines are so powerful that the user must be fluid across the floor. Pausing, dropping the clutch, or hitting a wall will result in gouges that will be visible on the finished floor. Excessive or deep gouges may require the floor to be re-sanded or replaced.

Floor edger

Floor edger


Once the floor has been sanded and old coatings have been removed, the floor can be spot-filled with water-based putties. I generally walk over the floor and fill any nail/ tack holes, missing knots, or larger butt joints that have been exposed during sanding. I never recommend flood or trowel filling a floor with liquid putty. Wood floors are a natural product and will expand and contract due to variations in climate conditions. Flood-filling floors with putty will eventually result in putty cracking and falling out between the gaps in floorboards. Filling gaps between floorboards is not considered an industry standard, so I leave the decision to the homeowner or end user.

2. Floor Polishing

Once the floor has been sanded, it must be polished to remove the fine marks left by belt and edge sanders. These marks may not be noticeable to an untrained eye until the floor has been stained or coated. Professional floor refinishers use single, multi(or a combination of both)rotary floor polishers, which may vary in size. These machines are complicated to handle as they tend to “throw” the user around the room until they learn to balance them while polishing. Polishing is a critical process when refinishing, as this is the final sanding step before staining and coating. The fine sanding discs and screens used with rotary polishers vary depending on the species of wood and type of finish used to coat the floor. I also use a smaller, handheld, rotary polisher for the edges, stairs, and any area larger polishers cannot reach. Polishers must be connected to a commercial dust control vacuum as they produce large amounts of fine dust that will cover your home and walls if used without dust control. Rotary polishers are not widely available in rental stores due to their difficulty operating. As an alternative, rental stores offer a “square buff” style machine, which is only effective at “cutting back” or fine polishing between coats or when recoating.

Floor polisher 320x180 1
Floor polisher

3. Floor coating

  1. By now, you will have decided on your floor finishing products and have purchased the equipment to apply them correctly. These include but are not limited to a painter’s pole, brush, applicator, roller, bucket, tray, gloves, non-marking old shoes, respirator, and cartridges. If oil-based finishes are chosen, solvents may be needed to clean your equipment after each use. Once you are ready to apply the coat, vacuum the floor, including baseboards and surrounding area.
  2. Monitor the ambient temperature and relative humidity before you coat the floor. These are essential factors for a professional floor contractor and the key to a successfully finished wood floor. Temperatures should not be too far above or below 20 degrees Celsius. If you stain your floor, it may need to be water-popped(depending on the species)to allow stains to absorb evenly.
  3. The first clear coat can be applied after the sealer or stain has dried. After the first coat has dried(refer to manufacturer recommendations), spot-filling any missed areas before coating the floor can be completed. This can be done with compatible colour-matched putty or fill products. When satisfied that you are ready for the next coat, you can begin the cutback and polish stage with a rotary polisher or buffer fitted with very fine sanding screens or conditioning pads.
  4. Once the floor has been “cut back,” thoroughly vacuum the areas. The final coat is the most essential part of the entire floor refinishing process, and complete care should be taken to ensure even application and drying. Floor coating is a skill that most professional contractors take years to master, so don’t be disappointed if your floors show signs of flooding, pooling, bubbling, lap lines, or missed spots. To apply a floor finish correctly, you must always apply evenly and quickly while maintaining a wet edge.

The final finish

I find successfully refinishing a wood floor extremely satisfying, even after 20+ years of refinishing floors. I still experience challenges here and there, but the skills I’ve acquired allow me to overcome and work through them. The physical aspects of the job are becoming more noticeable as I age, and my days of refinishing a wood floor are numbered. For this reason, I am happy to help others and supply all the necessary finishes, paper, tools, and accessories when refinishing a wood floor. If you choose to sand and refinish wood floors, please look at my available products. I can help you plan and supply materials that will help you refinish a wood floor and likely save you time and money by avoiding wastage and mistakes.

More useful information…

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