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Which flooring finish is best? Let's dive deep!
When you're considering flooring finish, the best choice is easy: UV-cured, satin polyurethane. Let's make our case.
Shopping for flooring or planning to refinish your own floor can be a challenge because there are so many complexities in the process and jargon involved.
For example, all flooring materials including wood, bamboo, plastic, or tile, need a finish treatment applied to the top layer. In common language, these treatments can be described as as a "protective coating", a "sealant coat", "varnish", "polyurethane", "urethane", "oil-rubbed", "oil-based", or "water-based." However, not everyone knows the differences between these specific flooring components, and many of these chemical classes overlap. So it is always wise to ask whether the person you're talking with is referring to a specific chemical or brand, or a whole class of protective top-coats--just to make sure you are on the same page!
If you aren't sure about the different between different kinds of flooring finishes, don't worry! We analyzed all of the wood flooring finishes to make final decisions regarding our own solid hardwood floors, and here, we break down all of the details that can help you make an excellent choice for your own interior flooring.
What is a flooring finish and what is its purpose?
The finish layer on a floor serves multiple purposes, all of which contribute to enhancing the overall quality and appearance of the floor. Most importantly, good finishes should improve the surface look, giving it a polished and refined appearance. The finish treatment also should make the material more resistant to wear and tear, prolonging its lifespan and durability. Finally, the finish also plays a role in making the material easier to clean, ensuring that maintenance is a breeze.
Choosing not to apply a finish to the flooring surface can have detrimental consequences. For instance, in the case of tile flooring, unsealed grout can absorb moisture that can harbor mold growth. This not only poses health risks but can also cause damage to the subfloor. Similarly, wood flooring without a finish is more susceptible to scraping and denting, which can significantly impact its appearance and integrity. Moreover, unfinished rough surfaces are notoriously difficult to clean, making regular maintenance a daunting task.
In the image of a Steller Ash hardwood floor above, the reflection from the outside light is diffused by the satin polyurethane finish (rather than a glossy or mirror-like finish). If the flooring finish was flat, this dark brown floor would appear darker, and the room would feel darker overall.
Considerations for how to choose a flooring finish
Is your flooring factory finished, or site applied?
In the past, flooring finish was always applied on-site out of necessity. However, with the advancements in construction practices and the refinement of factory-applied finishes, the landscape has changed. Nowadays, most high-end wood flooring materials come prefinished, allowing manufacturers to have precise control over the final product's aesthetics and consistency. Site-applied stains and finishes can still result in a beautiful and durable finish when done by experienced professionals, but it's crucial to ensure that your on-site finishing team has extensive expertise to achieve the desired outcome.
"When our team founded Steller Floors, we decided to pre-finish all of our flooring for several reasons. First, we wanted to make sure that all of our floors were treated with a consistent appearance and resilience. Second, we wanted our floors to resist humidity and moisture in transit and on-site. Exposed wood can quickly respond to excess humidity or extremely dry conditions during shipping, and pre-finishing adds an additional layer of protection to ensure the quality of the material." - Evan Stover, Chief Innovation Officer
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How are site-applied finishes used?
In cases where an on-site, certified professional is applying an oil-based or water-based polyurethane to a floor made of solid hardwood, engineered or other natural material, the same professional is usually nailing or gluing down the primary material first and sanding the top surface smooth on-site. These initial steps can take several days or weeks, and then the applicator should be waiting for the dust to settle before applying the stain or first coat of finish.
If you are staining your floor to achieve a certain aesthetic, the applicator may stain the flooring separately or as part of the finishing process when stain is combined with the finish. Take care to know which application you will use in advance. In some cases, stains can have high VOC content, and you should not be living in your home when it is curing. Be sure to ask your chosen professional if you can read the labels on the materials that they will be using if you are planning to remain in your home during on-site finishing.
When the applicator applies the first coat of finish, they're often pouring large amounts of finish on the floor and spreading it out to the desired thickness. It is important that the applicator has significant experience and knows the correct thickness: too thin and the flooring won't be protected, too thick and the flooring finish won't cure properly before the next coat.
Many applicators will lightly sand between coats so that the second coat readily bonds to the first coat. In this case, the first application must FULLY cure before sanding. Alternatively, if they do not plan to sand after the first coat, they are likely to apply the second coat quickly after the first so that the second coat chemically bonds BEFORE the first coat is already cured. This second scenario has a high risk for improper curing, shoeprints, and hazy areas. Always use a professional for either of these approaches.
Common misconceptions about site-applied finishes
Because in the past all flooring was site-finished, there are many misconceptions about site-applied finishes. First, many folks believe that because site applied finishes are applied in thicker layers, that the flooring material is protected more fully. In fact the opposite is true. Thicker-than-recommended finishes in on-site applications can cause improper curing and cause the finish to become more vulnerable to wear.
In fact, flooring finishes that are applied in the factory and on-site are chemically quite similar, and so should be applied at thicknesses. In addition, UV curing in factory-controlled environments helps accelerate the curing process so that chemical bonds are more common throughout the finish surface--which makes it harder. Unfortunately, UV curing on-site is very uncommon.
A second common misconception is that some folks believe that because site-applied polyurethane sinks down in the cracks of the floor, that the flooring is better protected from water. In fact, no wood surface is completely water-proof, it is only water resistant. Micro-cracks in polyurethane appear in every natural flooring material over time, because the material itself becomes brittle with age and sunlight. At first, oil-based finishes may appear to resist water better than polyurethanes, but also break down with age and sunlight.
"For all of these reasons and more, we don't believe that site-applied finishes bring any additional wear protection or beauty to interior floors, and so we decided to remove a lot of the hassle and headaches for owners by taking care of finishing the materials at our own facility and shipping only pre-finished materials." - Evan Stover, Chief Innovation Officer
What is better: Oil-based or Water-based flooring finish?
First things first: we need to get specific about the chemistry that we are discussing! Most flooring finishes are made of three components: (1) small particulates of the final finish (usually a urethane monomer or oil), (2) a carrier that helps the finish particulates spread (usually water or an oil like mineral oil), and sometimes (3) a chemical that accelerates the reaction, like alcohol or a UV-reactive catalyst.
Varnish and Shellac: These fairly old-school floor finishes can be used on floors because they form a cohesive wear-resistant finish. However, these finishes typically use a mixture of natural, plant or insect-derived materials, and can become sticky with age. They can also patina, or turn yellow, more quickly than modern finishes because they are applied in thick layers. In general, we do not recommend using these finishes unless you have consulted carefully with a professional. Luckily, in the last 50-100 years, polyurethanes were developed specifically to provide advances over these original finishes.
Water-based polyurethane: In modern, water-based polyurethanes, water is the carrier, polyurethane is the final wood floor finish, and evaporation accelerates the reaction alone. That is, as the water evaporates, small urethane molecules drift close to one another and bond to form a surface of polyurethane. These finishes are some of the most advanced materials because they have been in heavy development over the past 20 years to make flooring more beautiful and wear resistant Broadly, these finishes are low VOC, and they are far less flammable than oil-based finishes.
Oil-rubbed finish: Despite the risks of using oil-based finishes, some folks prefer the idea of a more historic aesthetic, and still choose oils. In oil finishes, oil itself sinks down into the pores of the natural material. If real oil-rubbed finishes are the finish you're using, it doesn't cure or dry--it just sinks in--which can take weeks. In some cases, alcohols are added to accelerate the reaction, but these high-VOC compositions have become far less popular over the years because they can harm both inhabitants and workers.
Oil-based polyurethane: The case for oils is similar to many oil-based polyurethanes, where the polyurethane coating is the final finish and oil can carry the material deeper into the material. In cases where alcohols accelerate the reaction, it also becomes less tolerable to work with. In general, oil finishes do make wood more water and wear resistant than bare wood, but they break down over time, and can "walk off" by attaching to shoes and socks and that's why oil-based finishes tend to need refinishing more often.
UV-cured polyurethanes: Most factory-applied floor finish is 100% solids, which means there is no water or oil carrier. In factory settings, urethane molecules with a minor additive of UV-activated catalysts are rolled with a roller-applicator. Once the finish is flat, it is exposed to high-power UV lamps that encourage the polyurethane surface to bond quickly and evenly through the layer. On occasion, custom additives can modify sheen and add slip-resistance (silica sand) or help prime the base material (other acrylics), but these additives are effectively "frozen" in the cured polyurethane layer.
"By far, I have been most satisfied with our UV-cured applications of polyurethane. They are crystal clear, resilient to wear, extremely low VOC, they cure homogenously and help seal the wood against water both in transit and in the final setting. What could be better than that?" - Evan Stover, Chief Innovation Officer
Aluminum Oxide: In the 1990's aluminum oxide was a popular additive for polyurethane/prefinished hardwood floors because it was very hard, and added additional wear resistance. However, as time went on, folks discovered that the additive was SO hard that you need to professionally sand the floor significantly more than is required for a standard polyurethane--which reduces the lifespan of the floor. Because you gain additional hardness but reduce the lifespan of the overall material, the additive has fallen out of favor.
One huge advantage of UV-cured polyurethanes is that they can be refinished with any standard water-based polyurethane in a matching sheen from a hardware store. Simply sand any scratches or dents using 220 grit sandpaper, and apply a touch-up coat. Then, let the material air dry before use according to the manufacturer's recommendations.
What sheen of flooring finish should I choose?
Once you have chosen your flooring finish (we vote for UV-cured polyurethane), and you have chosen where it will be finished (we would choose factory-applied), all that's left is to decide which sheen is best. We're here to make that easy on you too!
The sheen of a floor is primarily determined by how reflective to light it is. There are scientific ways to measure reflectance, but there are some easy-giveaways that you can see with your own eyes. Raw polyurethane is glossy, and you can tell when lights reflected in the floor look like mirrored reflections. In order to make the reflection look dimmed or more diffuse, dulling agents are added to the finish--the more agents are added, the more diffuse the reflection appears.
Generally speaking, finishes are divided into categories of sheens: high-gloss, semi-gloss, satin, designer satin, and flat (the most dull).
Gloss and Semi-gloss Finish: While gloss and semi-gloss finishes were very popular in the 80's and 90's (and resulted in very shiny floors) they have fallen out of favor because they quickly reveal scratches and dents. In part, this is because scratches and dents almost never tear the polyurethane, and instead the floors crease the wood underneath. Then, shifts in the light follow the shape of the scratch and make it stand out.
Satin Finish: Satin and designer satin finish sheens have become quite popular in hardwood floors in recent decades. In particular, they offer numerous benefits that make them an ideal choice for hardwood floors. For example, they seamlessly blend with any design style, making them versatile and adaptable to various interior aesthetics. They also tend to disguise minor scuffs and scrapes or pet damage, because light is diffused across the surface. When the floor is dirty, it tends to look more dull, but if you prefer a clean look, satin finishes still have enough shine to polish up a room.
Flat Finish: Interestingly, flat finishes are more recently gaining traction because they can give the appearance of unfinished natural wood. While this sheen can undoubtedly hide a large number of flooring imperfections, it can often appear dusty or dirty because it reflects so little light--it may also be more difficult to determine when the wood needs to be refinished. In some spaces, including the very-deep south and beachy areas, reducing the amount of indoor light may be desirable, but it is good to take care in seasonal climates so that rooms do not feel too dark during the winter.
"Satin polyurethane finishes, in particular, offer the perfect combination of resilience and beauty for hardwood floors. Their versatility, ease of cleaning, and ability to disguise scuffs make them the ideal choice for any interior space. So, when it comes to selecting a sheen for your hardwood floors, we have opted for satin because it is undoubtedly the stellar choice."- Evan Stover, Chief Innovation Officer
What flooring finishes does Steller Floors use?
As you can tell, our team has carefully considered which finish compositions are the best choice for our innovative, solid hardwood floors in the vast majority of cases. Because of its resilience and unique ability to balance reflected and diffused light, our standard, durable hardwood floor finish is a UV-cured, factory-applied 100% solids polyurethane in a satin sheen. As needed, we can use additives for slip resistance or colorants.