Choosing the Right Finish for Hardwood Floors
Many considerations come into choosing the proper finish for a hardwood floor. Does the homeowner want a quick-drying product that also protects the surface of the wood? An oil-modified urethane that creates a warm, amber hue? Or a penetrating oil that soaks deep into the fibers for a natural look? We spoke with manufacturers in the segment about the pros of cons of each type of finish, what to expect when working with these products and what new technologies are available.
Waterborne vs. oil-modified finishes
Heather Lindemann, Bona US public relations, said that waterborne finishes offer several benefits over traditional, oil-modified urethanes (OMUs). “The main advantages for choosing waterborne finishes are the low odor, non-flammable qualities as well as the ability to apply multiple coats in a day, faster drying (two to four hours) and curing (seven to 14 days; Bona finish cures in three days), low VOCs, no need to abrade between coats and non-yellowing.”
She acknowledged that waterborne finishes are generally more expensive and require more training than OMUs. “Waterborne finishes can be more difficult to apply because they dry faster. Some might also say that waterborne does not offer the depth of oil—however, that is typically the case only with high-sheen finish which is not the current trend.”
Regarding OMUs, Lindemann noted that they “provide a rich, traditional amber look to the floor. It is also easy to use as it has long open times. However, oil-based finishes will turn yellow and darken as they age, and are flammable with high VOCs.”
She added that applying an OMU can be time-consuming. “The typical process for oil-modified is one coat per day (and sometimes may take three to five days between coats). Dry time is eight to 24 hours and curing is 14 to 30 days. One must abrade between coats and use mineral spirits to clean up (adding more VOCs to the project). Note that VOC regulations are affecting ease-of-use and dry/cure times for oil-modified finishes, as some regions have to use higher-solids products with slower drying ‘packages’ (which equals a higher rate of poly beads) to get the VOCs within limits.”
According to Josh Neuberger, marketing manager for Uzin Utz’s Pallmann division, the technology behind waterborne finishes has advanced at a rapid pace. “Most waterborne finishes are under 200 VOCs while most oil-modified urethanes are 350 or above and many are closer to 450 VOCs. The technology now exists where a user can achieve the deep ‘oil’ looks of an OMU while staying in a waterborne system.”
Waterborne systems should also be considered when a lighter look is desired. “A good example of this would be on white oak or maple where the typical rationale for choosing these types of woods is to keep things as light as possible. This can be achieved very easily with a waterborne system,” Neuberger noted.
Whatever product is ultimately chosen, Tony Ziola, MAPEI’s business development manager for Ultracoat systems, said installers and contractors should “be aware of the general characteristics of each type of finish, including dry time, cure time, inter-coat abrasion, finish application method, clean up method, coverage, appearance, whether the finish is flammable or combustible, health hazards, local VOC restrictions if any, and disposal.”
Neuberger added these questions to ask about the finish: “Can it be applied with lambswool or must it be in a T-Bar application? Can it be rolled? What is the sq. ft. coverage of the finish, as this will affect the durability of the finish. Also, environmental factors such as temperature and humidity will affect each finish differently.”
Keith Hardisty, marketing manager for Rubio Monocoat USA, said hardwax oils should be chosen when the end-user wants to keep the natural look and feel of the wood. “Many hardwax oils will apply in a single coat, saving labor and material costs. If the floor is damaged, local repairs can be achieved without sanding and refinishing the entire floor.”
According to Lindemann, penetrating oils and associated hardwax oils do not leave a protective layer on top of the floor like a waterborne or oil-modified polyurethane. “So the wood surface will take the brunt of wear and tear. Typically, hardwaxes need more ongoing maintenance as the oil and color wear away.
“While it may be recommended, an additional coat of hardwax oil is not always necessary to further protect penetrating oils. Adding hardwax oil can make re-oiling and regular maintenance more difficult.”
Ziola noted, “OMUs and water-based finishes are ‘surface build’ finishes, meaning they sit on the surface of the wood flooring. A hardwax oil finish penetrates into the pores of the wood rather than sitting on the wood’s surface. The choice of finish is up to individual style. Natural oils give the wood flooring a more natural, low-sheen, warm appearance. The floor can be left natural or the homeowner can choose a custom color.”
Neuberger explained penetrating finishes this way: “They work by absorbing into the wood and creating a protective bond with the wood fibers inside. This is how the finish gains its strength and durability, by penetrating into the wood deeper. Urethanes (whether oil- or water-based) gain their strength by multiple coats being applied to the floor.
“Since penetrating finishes go down into the wood fibers they will typically produce a very flat or ultra-matte sheen appearance to the floor. If a project owner wants this look, then penetrating oils are the way to go. It should be noted that it is a good idea to consider maintenance schedules on these finishes, and each manufacturer’s recommendations on applications and maintenance is different.”
Finishes for sports floors
Lindemann stated that most sports floors are coated with regular waterborne and oil-modified topcoats; prefinished and LED-cured finishes occupy “a very small niche in the market.”
She added, “UV prefinished (usually only pre-sealed) finishes are more difficult to recoat and it can be challenging to get game line paint to stick, which is key to successful sport floors. LED-cured finishes are simply waterborne finishes with photo-initiators to speed the curing when exposed to the LED light.
“While it can be beneficial, it is still critical to appropriately apply the product and to make sure 100% of the floor is LED-cured to create consistent performance. Bona Sport waterborne finishes, for example, are 90% cured in 24 hours so placing these floors back into play right away is not a problem (thus no big need for the prefinished or LED-cured systems).”
Ziola stated that UV-cured finishes prevent early damage caused by athletes getting back onto the gym floor prior to the finish being completely cured. “Some studies have shown that a water-based, UV-cured finish is more scratch-resistant, scuff-resistant, wear-resistant and more durable than two-component water-based finishes.”
However, with that advantage comes one major disadvantage, he added. “UV-cured water-based finishes can be considerably more expensive than OMUs, plus there is the additional cost of the UV equipment, employee protective gear and training.”
We asked the manufacturers in this story to share a little more information on their latest finishes. This is what they had to say.
Bona: “Traffic HD continues to be Bona’s flagship waterborne finish. Bona Traffic HD is one of the lowest VOC products on the market with the best overall durability, chemical resistance, and incredible ease-of-use (flow, leveling, defoaming).
“Bona continues to bring additional colors to our waterborne sealer assortment—adding NaturalSeal and NordicSeal two years ago. Bona IntenseSeal brings out the natural coloring of the species being coated and gives stain colors some extra pop. One to two coats of AmberSeal will provide an oil-modified look while keeping it in the waterborne system. NaturalSeal (with just a hint of white pigment) gives the look of a freshly sanded floor (especially when combined with Traffic HD Extra Matte or Traffic Naturale finish). One to two coats of NordicSeal (again, based on addition of white pigment) will provide a traditional white-washed look to any species.
“The traditional BonaSeal provides a Scandinavian, slightly washed-out look to the floor. All seals are offered prior to coating with any number of Bona waterborne finishes.”
MAPEI: “MAPEI finishes are all water-based. MAPEI’s Ultracoat line of wood flooring products consist of a two-coat system or an optional three-coat system. Depending on the flooring and expected food traffic, installers have a range of options to choose from.
“The MAPEI 2-Coat System features a two-component sealer, Ultracoat Premium Base, and a two-component finish, Ultracoat High Traffic. When used together they have the build of most three-coat water-based systems.
“Ultracoat Easy Plus and Ultracoat Universal Base is a one-component sealer and finish great for residential and light commercial projects due to quick dry times (two hours and one hour respectively).
“Ultracoat Aqua Plus is a liquid binder mixed with fine sanding dust during the final sanding process, which makes wood filler that can be used to fill voids and cracks. It takes on the same stain as the flooring because it’s made from the sanding dust of the floor. This product is more elastic than ready-to-use fillers and is ideal for woods that are very photo-sensitive.
“Ultracoat Toning Base is a two-component sealer that is a color enhancer. It enhances and accentuates the wood species’ natural color.”
Rubio Monocoat USA: “Our interior finish product is called Oil Plus 2C. It is a plant-based hardwax oil that is 0% VOC. Our unique technology creates a molecular bond with the raw wood fibers. This technology allows you to color (if desired) and finish wood in one single layer.”
Uzin Utz: “Our latest waterborne finish is Pall-X Power. Pall-X Power features advances in resin and polymer chemistry that have been specifically designed into the finish to give this waterborne finish two-component strength in a convenient, single-component product. Pall-X Power’s innovative formulation creates a strong, protective grid across the entire floor surface that provides the ultimate wear resistance and outstanding chemical resistance while its superior flow and leveling properties leave a floor that is stunningly beautiful.”