Polyurethane, “Swedish” finish, Moisture cure urethane, and Water-based urethanes, to name a few, are blends of synthetic resins, plasticizers, and other film-forming ingredients which remain on and protect the surface of the wood. All are durable moisture-resistant finishes. These finishes are generally available in high-gloss, semi-gloss, satin and matte, except moisture-cured urethane. Any one of the above surface finishes is a good choice. They are the recommended finish for kitchens or similar areas where there is exposure to water splashing or spills.
Note: Penetrating sealers may have also been used as an undercoat for surface finishes.
“Polyurethane,” oil modified polyurethane, is generally the most common surface finish. The finish tends to amber slightly as it ages.
“Swedish finish,” acid curing urethane, is also a very durable finish, generally harder than polyurethane. These finishes are clear, fast-drying and resist yellowing.
Moisture-cure urethanes are the hardest finishes. Some are non-yellowing (check can label). Gloss is the most common sheen.
“Water-based finishes” are urethanes or blends of acrylics and urethanes that are fast drying, moisture resistant, durable, and resist yellowing. As the name implies the vehicular component is water.
Most manufacturers of surface finishes recommend no waxing. Wax will, in most cases, be slippery. Once waxed, the floor may not be successfully refloated to rejuvenate it, but will have to be completely sanded down to raw wood to restore the finish.
“Varnish Shellac and Lacquer finishes.” These surface finishes are rarely used today, and generally are not considered as durable as the more modern finishes. Shellacs are the softest and show water spots. Varnishes are harder but not to the extent of modern finishes and will show more ambering over time. Lacquers are hard and brittle and scratch easily (very flammable when applied).
Don’t damp mop shellacs because of water spotting. You can use a slightly damp mop on the others if not previously waxed. For finishes which have been previously waxed, maintain by waxing occasionally. When traffic wear is noticeable, complete refinishing and changing to a newer finish is most often the preferred choice for repair.
“Polymer finishes.” There is a third classification of finishes known as acrylic impregnated or an irradiated polymer. This is used primarily in commercial applications. Each brand of flooring using a polymer or acrylic impregnated finish have specific maintenance procedures which should be obtained from the manufacturer.
Caring for Surface Finishes on Your Floors
Vacuum and/or dust mop regularly.
For general cleaning of soiled areas, dip or spray a clean cloth with the manufacturer’s recommended cleaner. The cloth should be slightly moistened, not wet. As you clean the floor follow by wiping the floor dry. If manufacturer of the finish is unknown, spray-mist areas of floors with a mild cleaner (i.e. non-abrasive counter-type) follow by wiping with a sponge mop or cloth pad mop, and dry up residue.
Note: Spray mist only as necessary. Do not apply moisture unnecessarily, vacuum instead. Contact the finish manufacturer to determine specific recommendations for cleaning the finish. Ammonia will damage or dull many surface finishes and should not be used to clean your floor.
Repairing a Surface Finish
With special care and skill, you may be able to repair polyurethane finishes yourself. Such repair may be necessary after stain removal or water damage. Use steel wool or fine sandpaper to remove layers of the finish from entire length of the affected boards. If necessary, stain and let dry completely. Apply the same type of polyurethane as the original finish to the entire boards, being careful not to build additional finish coats on surrounding strips. Read application directions. Taping the perimeter of the area with a quality release masking tape is helpful. Allow ample drying time. After the finish is dry remove tape.
Caution: Don’t attempt this if you have an older varnish. The older finishes are almost impossible to repair and match successfully. Lacquer and shellac, however, repair more easily.
For a small, relatively inconspicuous area you might get by cleaning with steel wool followed by paste wax. You won’t get an exact match but it could serve as temporary repair. The alternative is sanding to expose bare wood over the entire room and applying new finish.