Factory-coated flooring products save time and provide a tough, guaranteed finish.
Recent advances in pre-finished flooring make a strong case for using these factory-finished products. More choices in surface finishes, a wider-than-ever selection of wood species and color choices, decorative borders and inlays, and improvements in the installed appearance are the main factors in the growth in popularity of these materials. And just like a site-finished floor, a properly installed and maintained factory-finished floor can last a lifetime.
Pre-finished Advantages
An obvious benefit of any pre-finished flooring material is that the completed installation takes less time; sanding, surface preparation, and finishing are already taken care of in the factory. And once you're done, you're done. There are no callbacks for an unevenly cured finish or other finishing defects. With pre-finished wood flooring, what you see is what you get - if there's an off-color or wild-looking board, it's easy to pick it out before installation. Pre-finished wood provides precise coloration and a guaranteed finish.
Flooring Types
Pre-finished solid wood strip or plank flooring is sold in widths from 2-1/4 to 5 inches wide and varies in thickness from 1/2 to 3/4 inch. It is always end-matched, which means that it has a tongue-and-groove profile on all four edges. The long edges, and usually the ends, feature a slightly eased edge or a pronounced bevel. The surface is stained or left natural and coated with up to seven layers of a clear, film-forming or penetrating oil finish. In all other respects, this product looks and handles like unfinished flooring and is nailed or stapled down. Thinner, 1/4- and 3/8-inch strips are also available and are either stapled or glued down. Generally, the thicker the strip, the more stable the flooring.
Engineered wood flooring. Industry sources estimate that pre-finished flooring accounts for at least 60% of the wood flooring market, with 37% of that portion represented by engineered wood flooring. Engineered flooring is made from cross-laminated hardwood or softwood layers, topped by a plain-sliced or rotary-cut wood face veneer. To ensure that the flooring can be repeatedly sanded and refinished, look for a minimum 1/8-inch-thick wear layer. The best grades of engineered flooring have a wear surface roughly equal to the thickness of the wood above the tongue and groove of a solid wood strip, making it just as sandable (for refinishing) as a solid wood strip.
Engineered flooring is often preferred in the South, where concrete slab construction is common. Glue-down or "floating" installation methods are typically used to install a wood surface over concrete. It's important to note that some, but not all, manufacturers warrant their product only when used on or above grade, not below. This doesn't rule out a wood floor for the basement room, but check with the manufacturer before you install a product underground.
Micro-bevels. Contrary to popular assumption, not every factory-finished strip has a pronounced beveled edge to conceal milling irregularities. In fact, manufacturers compete to have the smallest eased edge, or "micro-bevel." The technology for producing pre-finished wood flooring has advanced to the extent that many engineered wood lines are available with a true, square edge. The mating edges and surfaces of some lines of engineered planks are so uniform that the manufacturer promises no difference in surface plane from plank to plank. Ironically, micro- and more exaggerated bevels thus become design options, described in certain product brochures as providing a "handcrafted look."
Pre-finished wood flooring is available in many species, including oak, maple, cherry, hickory, butternut, beech, pecan, ash, merbau, and more. Soft and "hard" pine are also available, as a wear layer over a hardwood core. Even with a selection this broad, however, you may not find exactly what you're looking for. Customization of colors and finishes is limited in residential lines. A few manufacturers offer custom short runs to residential builders to match or complement other architectural features. Not surprisingly, there's a nominal custom-color setup charge. Even in commercial flooring lines, minimum 10,000-square-foot orders may be required to justify a custom color run.
Whether pre-finished or unfinished, tongue-and-groove solid strip or plank flooring occasionally requires some force to install. You have to be more careful and take a little more time with a pre-finished plank, though, because damage is more difficult to repair. Because it isn't nearly as prone to twisting and warping as solid lumber, engineered flooring typically matches up easily and can be more quickly installed. Avoiding uneven surfaces between adjacent boards requires a sharper lookout during installation because you won't be sanding the surface to make them flush. Accumulating dust, debris, and defects in the subflooring can keep the strips or planks from lying flat. The evenness of the finish surface depends not only on the milling tolerance of the manufacturer, but also on the smoothness of the subfloor.
Floor Finishes
The principal complaint from homeowners about any hardwood floor is the vulnerability of the finish to scratches. Deep scratches leave the wood prone to water damage and staining. Shallow scratches can be spot-treated with various touch-up products, but once the floor has reached an overall degree of dullness from wear, the only option is to refinish it. If not deeply scratched, flooring with an acrylic or urethane finish can be rotary screened and recoated with good results. A badly worn or abused area, such as in an entry or hallway, probably requires re-sanding and refinishing of the entire floor. This is no small job and defeats one of the main reasons for installing factory-finished flooring - avoiding the dust, disruption, odor, and scheduling of a site-finished floor.
Aluminum oxide. Site-applied finishes are no match for the latest generation of reinforced urethane coatings, available only as a factory-applied finish. Most manufacturers now offer some version of a urethane finish enhanced with aluminum oxide. It's like ordinary urethane on steroids, making the wear surface far more durable than one with an un-enhanced site-applied coating. The aluminum-oxide crystals are suspended in multiple layers of ultra-violet cured polyurethane, resulting in a surface that's claimed in more than one brochure to be "ten times more abrasion resistant than traditional urethane finishes."
Some reinforced finishes are slightly rough to the touch, due to the hard crystal content. Mannington has recently introduced its "Scratch-Resist" finish, which employs two sizes of aluminum-oxide particulate, one far smaller than the other to act as a filler between the larger particles. This makes the surface more consistent, in terms of both hardness and smoothness of finish. Because aluminum-oxide crystals are clear, such finishes are just as clear as an ordinary urethane coating.
Ceramic, diamond, and titanium also turn up in various manufacturers' urethane finish formulations, alone or in combination with aluminum oxide. All are invisible in suspension and serve the same purpose. Product literature doesn't convince me that there's any clear advantage of one formula over another. Manufacturers offer 10- to 25-year warranties on their enhanced finishes, assuming normal use and maintenance.
Other Finishes
Many types of pre-finished flooring can be ordered with traditional finish coatings. Among the coatings available are wax, urethane, water-borne acrylics, and penetrating oils. You can expect these finishes to perform identically to site-applied equivalents. The main advantages of pre-finishing are uniform appearance and faster completed installation.
Acrylic-wood is a unique finish option, available in 3/8-inch-thick engineered strip and plank flooring. The nominal 1/8-inch-thick wear layer of an acrylic-wood floor is solid, natural, colorized acrylic-impregnated wood with a clear, satin-like finish. In the impregnation process, liquid acrylic is forced into the porous cell structure of the wood wear layer, then permanently hardened by heat or gamma irradiation. The flooring is designed to be installed by the direct glue-down method on concrete or plywood underlayment. Its primary application tends to be commercial, but it's appropriate and available for residential use too. Because the color and acrylic finish run all the way through the wear layer, the surface is said to be anywhere from three to five times harder than ordinary hardwood and highly resistant to impact. Deep scratches can be spot-repaired by buffing or localized sanding. If you want a high-gloss surface, you can even buy acrylic-wood flooring with an aluminum-oxide urethane finish.
Things to Consider
A pre-finished floor should be one of the final materials installed in a new home. Ideally, the home's heating or air-conditioning system should be up and running. Drywall and tile work should be fully dried, all but the final woodwork and trim should be completed, and the interior temperature should be maintained at minimum 60ºF before and during installation. Don't open flooring packages until you're ready to install them. Flooring should be installed mixing pieces from several cartons at once to ensure a good blending of color and shade mix. Dye lots are unlikely to match for later weave-ins, should a patch or repair become necessary. It's a good idea to order a little extra material and store it away on site for this eventuality.
Allow an expansion space around the entire floor perimeter, equal to the thickness of the flooring. In a high-moisture region, strip flooring should be spaced approximately 1/32 inch apart to accommodate normal seasonal dimensional changes. Temporary aluminum spacer strips, inserted every 8 inches or so, will prevent individual rows from being drawn up too tightly. Install at least 6 rows of strip flooring before removing or relocating the spacers - to keep track, move only the rear row of spacers forward as you complete each subsequent row.
Care and Feeding
To protect any wood floor from accidental scratches, homeowners should use felt pads under furniture legs and sweep or vacuum frequently to remove abrasive sand and dirt. Periodic waxing maintains and restores the original shine (but don't wax unless you've installed a wax-finish product in the first place).
Most manufacturers offer products for routine maintenance of their pre-finished wood flooring. There are proprietary cleaners for sticky food spills and rubber heel marks; touch-up kits are also available for light scratches, burns, and other kinds of minor damage. As a professional courtesy, leave a maintenance kit behind with every pre-finished floor you install.
Dave Holbrook is an associate editor at our sister magazine, The Journal of Light Construction; www.jlconline.com.
