Wood flooring

Wood flooring is a type of flooring made from the timber of hardwoods, or of spruce or hard pine. There are two basic manufactured types of hardwood. Wood flooring comes unfinished, and once installed is sanded, then finished on site. More modernly, the product is pre-finished in a factory. The products that are pre-finished are often a polyurethane finish that has added aluminium oxide, however some companies use titanium dioxide or other oxides instead. These metal oxide finishes are used in various types of floor coverings and increase the wear a hardwood floor can handle.

Types

olid

Solid hardwoods are typically 3/4" or 19mm thick, although some do come in 3/8" (10mm) or 5/16" (8mm) thicknesses. Typically the wearing thickness, i.e., the thickness that can be sanded over the lifetime of the floor, above the tongue-and-groove portion, is approximately 7/32" approaching 1/4". This type of hardwood flooring can be installed with a nail-down installation method over wood subfloors. This type of hardwood is also very susceptible to the effects of moisture and temperature, because hardwoods expand and contract with moisture and temperature changes in the atmosphere. Since hardwoods expand and contract in the width of the grain, this type of hardwood flooring is not recommended to be installed over a concrete slab, unless otherwise stated by the manufacturer. There are some instances where 3/8"-thick solid hardwood can be installed on a concrete slab.

Engineered

Rather than having one solid piece of hardwood, the engineered hardwood method uses layers of hardwood veneer to create a product that can range in thickness from 3/8" or 8mm up to 9/16" or 14mm thick. The wood veneer can range in thickness depending on the manufacturer, as will the top wearing thickness. In order to create an engineered hardwood, these veneer layers are stacked one on top of the other with the grain of adjacent layers oriented perpendicular to one other. Once the desired thickness is achieved, the boards are then cut into the correct board width. From there, the boards are then manufactured to have a tongue or groove on the edges. The final step is to add stain if necessary, and add a finish. By doing this, the engineered hardwood becomes less susceptible to the effects of moisture and temperature change, because wood expands and contracts in the width of the grain direction. Therefore engineered hardwood is referred to as being dimensionally stable. Solid hardwood does not have dimensional stability because all of the grain runs in the same direction. Because of its dimensional stability, engineered hardwood can be glued directly to concrete above or below grade, as opposed to solid hardwood which cannot.

Manufacturing

There are three ways engineered hardwood floors are manufactured.

Rotary-peel

This process involves treating the wood by boiling the log in water at a certain temperature for an allotted amount of time. Then after preparation the wood is peeled by a blade from the outside of the log, and it works its way around the log toward the center, creating a wood veneer. This veneer is then pressed flat with high pressure to make the veneer flat. This style of manufacturing tends to have problems with the wood cupping or curling back to its original shape. This problem is commonly known as "face checking" and is a manufacturing defect. Rotary-peeled engineered hardwoods tend to have a plywood appearance in the grain.

liced-peel

This process involves the same treatment process that the rotary peel uses. However instead of being sliced in a rotary fashion, this style of wood is sliced from the end of a log. From there it goes through the same manufacturing process as a rotary peeled product. However this style of engineered hardwood tends to have less problems with "face checking" and also does not have the same plywood appearance in the grain. However, this product can tend to have edge splintering and cracking due to the fact it has been submersed in water and then pressed flat.

Dry solid-sawn

Instead of boiling the hardwood logs, in this process they are kept at a low humidity level and dried slowly to keep moisture from inside of the wood cells. The manufacturing process to get this top veneer layer is similar to how a solid hardwood is manufactured. This style of engineered hardwood has the same look as solid hardwood, and does not have any of the potential problems of "face checking" that rotary- and slice-peel products have, because the product is not being exposed to added moisture.

Floor Finishing and Sanding

Sanding provides a method for smoothing an installed floor, compensating for unevenness of the subfloor. Additionally, sanding is used to renew the appearance of older floors. No beveled edges, as seen in some premanufactured prefinished floors, will be evident in a sanded floor. Sanding using successively finer grades of sandpaper is required to ensure even stain penetration when stains are used, as well as to eliminate visible scratches from coarser sandpaper grades used initially. Prior to modern polyurethanes, oils and waxes were used in addition to stains to provide finishes. Beeswax and linseed oil, for example, are both natural crosslinking polymers which harden over time. Modern polyurethanes, and polyester resins, used occasionally, are superior in toughness and durability.

Care of Wood Floors

The appeal of a properly installed wood floor is ease of care and maintenance. Proper use of vacuuming, sweeping, and damp mopping is usually all that is required to maintain the cleanliness and appearance of a wood floor. Like tile floors, excessive grit and foot traffic will affect appearance. Unlike carpet or rugs, a properly finished wood floor, like tile, does not accumulate hidden soil or odorous compounds.

ee also

*Reclaimed lumber
*Parquetry

External links

http://www.woodfloors.org/

http://www.nofma.org/