Recoating a Previously Finished Floor

A maintenance coat is one of the most important aspects of long-term wood floor care. In some cases, the state of the wood floor may not be severe enough to require a full sand and finish. In these situations, recoating the floor may be a viable option. However, there are several considerations to take into account when determining whether to recoat or sand and finish your customer’s floor.

First and foremost, the type and extent of the damage determines floor care. There are several types of damage that wood floors can sustain, each of which may affect whether recoating is an option for the floor:

  • Surface Damage: Dents, gouges, and scratches may be recoated, but will still remain in the flooring surface and may even become more apparent after the new coating has been applied.
  • Wear Patterns: Wear patterns indicate a loss of finish on the existing floor in high-traffic areas, typically resulting in exposed wood fibers. Wear patterns may be recoated to protect the floor from further damage, but will often accept the new coat of finish differently from the remaining flooring, will remain unsightly, and may become more apparent after the new coating has been applied unless addressed prior to the recoat.
  • Water Damage: Permanently cupped floors may be recoated, but will remain cupped, which may be more apparent after the new coating has been applied. Hand abrading and/or chemical adhesion systems may be required.

Next, it’s important to determine if there is any surface contamination (including wax, grease, and many other maintenance products) that can impact finish adhesion. It is important to test for the presence of these contaminants before recoating the floor to avoid failure.

Always clean the floor before testing for contaminants and before any maintenance coat. The process includes using a wood floor cleaning product recommended by the wood floor finish manufacturer. Cleaning the floor includes extraction of any dirt, debris, or contamination from the flooring surface as well as beveled edges, gaps, or open knots.

Always test in several areas of the floor to be sure the finish will adhere properly. The test areas should be used to check for contaminants as well as testing finish adhesion and compatibility. Closets may not be the best test area because maintenance products are often used on the main body of the floor, but not always in closets. Testing in one area does not guarantee acceptable performance or compatibility. Advise the client of this before proceeding.

There are different procedures for testing for different types of wood flooring contaminants. The following is more information about field testing for wax, acrylic polish, and grease or other mild contaminants.

WAX

Prepare a test site on the main field of the floor. Do not prepare the test site under area rugs, in closets, or under furniture. Thoroughly clean the test site to remove dirt and debris from the floor surface.

Mineral spirits or paint thinner will break down wax. Use a small amount on a clean, white towel or rag in an area that would likely be of concern. If a slight yellow or brown color appears on the rag, paste wax may be present, and caution should be exercised before proceeding.

Another test involves placing a few drops of water on the floor. If white spots appear after about 10 minutes, the finish may be wax.

If the floor has been waxed, rewax the floor whenever possible. When sanding a previously waxed floor to bare wood, be cautious of the remaining wax in the seams and soft grain of the flooring. The safest option is to go back with a wax finish to avoid adhesion issues.

ACRYLIC POLISH

Prepare a test site on the main field of the floor. Do not prepare under area rugs, in closets, or under furniture. Thoroughly clean the test site to remove dirt and debris from the surface.

Acrylic polish stripper or ammonia break down these contaminants. Place one to two drops on an inconspicuous area of the floor. If milky white spots appear after approximately two minutes, acrylic polish may be present.

If the floor is contaminated with an acrylic polish, it must be completely removed from the flooring before a new finish application.

Use extreme caution when chemically stripping any wood floor as not to damage the floor with excessive moisture. Be cautious of any remaining contamination in the seams, open and soft grain, and knots of the flooring. Resanding the floor may be the best option.

GREASE AND OTHER MILD CONTAMINANTS

Many wood floor cleaners and dish soaps will safely remove greases, oils, and other mild contaminants. Check with the finish manufacturer for recommended cleaning products and the chemical capabilities of these products.

Use these cleaners on a test site in the main body of the floor with a microfiber mop or a white towel.

It is very important to consider the porosity of the wood floor when testing or removing any contaminate from the surface. Even though the contaminate may be able to be removed, it may still also be in cracks, crevices, or open knots. Agitation and extraction in these areas will usually be necessary.

COMPATIBILITY OF FINISHES

Remember to check the compatibility of finishes: one brand or type of finish may not be compatible with another. Factory-finished floors that include a high-abrasion finish may need to be pre-treated with an approved chemical solution to promote adhesion, as recommended by the finish manufacturer.

Factory-finished floors that have finishes infused with Teflon cannot be recoated. To test for Teflon-infused finishes, use a permanent marker in an inconspicuous area on the finish. If it wipes away, Teflon is present. If it does not wipe away, carefully use a mild solvent like mineral spirits to remove from the surface and proceed with caution.

After application of finish in the test area, you can check to see if it has adhered. To test the adhesion of a finish on wood flooring, use the X-cut tape test.

The X-cut tape test is primarily intended for use at job sites on previously applied coatings, and will likely result in damage to the test area. Be certain to exercise caution and make your customers aware. Using a sharp razor blade, scalpel, knife, or other cutting device, two cuts are made into the coating with a 30-45° angle between legs and down to the substrate which intersects to form an “X.” The tape is placed on the center of the intersection of the cuts and then removed rapidly. The X-cut area is then inspected for removal
of coating from the substrate or previous coating and rated.

FINISH ADHESION OPTIONS

After the floor has been thoroughly cleaned, the contaminants have been removed, you have tested for compatibility, and you determine that recoating is your best option, you must next consider the best adhesion method for your floor. There are two basic ways a new finish will adhere to an existing finish: through mechanical adhesion or chemical adhesion.

Mechanical adhesion involves lightly abrading the top surface of the finish using abrasive pads or abrasive paper/screens, then applying another topcoat. Mechanical adhesion methods may not always be the best option for recoating all existing floors including some factory finished floors with high abrasion finishes; beveled edge floors; sculpted or reclaimed floors with high and low elevations where the abrasive may not physically scratch all surfaces; and floors that have been previously coated with natural oil finishes.

Chemical adhesion systems involve using chemical solutions in order to promote adhesion to the existing surface, then applying another topcoat. When using these chemical adhesion systems, use a complete system developed and approved by the finish manufacturer.

Steps for mechanical abrasion:

  1. Test the floor for contaminants and finish compatibility before accepting and scheduling the job.
  2. Load all tools, equipment, finishes, abrasives, etc., in the area of the floor where work will be performed to avoid potentially tracking in contaminants from outside and to allow the finish to get to room temperature.
  3. Inspect the floor for damage and areas of potential concern.
  4. Clean the floor in accordance with the finish manufacturer’s recommendations.
  5. Lightly abrade the old finish according to the finish manufacturer’s recommendation for abrasive type and grit choice. Use a rotary sander or multi-head sander with the recommended abrasive, always moving with the direction of the grain. Thoroughly abrade the entire floor without leaving noticeable scratches, which may be visible after the finish is applied. Lightly abrade all edges of the floor by hand with the same abrasive used in the field.
  6. Vacuum and tack the floor until all dust has been removed from the surface per NWFA Sanding and Finishing Guidelines.

Steps for chemical adhesion system:

  1. Test the floor for contaminants and finish compatibility before accepting and scheduling the job.
  2. Load all tools, equipment, finishes, etc., in the area of the floor where work will be performed to avoid potentially tracking in contaminants from outside and to allow the finish to get to room temperature. Vacuum the floor.
  3. Inspect the floor for damage and areas of potential concern.
  4. Clean the floor according to the finish manufacturer’s recommendations.
  5. Follow the manufacturer’s instructions for applying the chemical adhesion promoting product. Allow the adhesion promoting product to dry in accordance with the manufacturer’s instructions.
  6. Apply the surface finish at the proper cover rate using the manufacturer’s recommended applicator and procedure.

A recoat is a great option to offer your customers, especially in cases where the floor doesn’t have deep gouges and the finish hasn’t completely worn through. A recoat can restore the beauty of their floor without the need to displace them for the resanding process. One of the best customers to have is a repeat customer. Offering a routine maintenance coat is one simple way to keep in front of your customers. Not to mention the maintenance coat business is one that is untapped in the wood flooring industry. Once you gain the confidence to test for and deal with all of the potential causes for failure, the maintenance coat service is one that can add a nice source of business to your portfolio.

Brett Miller is VP of Education & Certification at the National Wood Flooring Association in St. Louis. He can be reached at brett.miller@nwfa.org.

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