Glossary

Aluminum Oxide
Refers to one of the newest and most durable finishes for wood flooring, that can only be factory-applied. Aluminum oxide is a suspension of aluminum rust particles in a urethane base. This finish is highly abrasion resistant, but slightly clouds the woods’ color and grain. In addition, pure aluminum oxide finishes cannot be screened and recoated. Therefore, the most high-quality prefinished products feature multiple base coats of aluminum-oxide, urethane mid layers, and hard anti-scratch top layers. These top layers can be screened and recoated, and provide the best balance between durability, maintenance, and clarity.

CSA
Refers to the Canadian Standards Association. Much like the SFI, this organization sets high standards for “wise use” of our forests. CSA certification ensures that the product comes from a responsible and renewable source.

Dimensional Stability
Refers to a wood floor’s ability to resist expansion and contraction (movement) with humidity swings. Some species of wood are much more dimensionally stable than others. In addition, engineered flooring products are substantially more stable than their solid counterparts.

Eased Edge
Refers to a square edge cut that has been rounded-off. This edge cut is essentially a combination of the square edge and microbevel.

End Match
Refers to a tongue and groove that is cut into the short edges of a wood flooring product. This product feature helps keep a floor uniformly flat once it is in service. Products that are end matched are often referred to as “four side tongue and groove”.

Engineered
Refers to a wood flooring product that is manufactured by gluing a hardwood veneer (layer) onto a plywood base. This type of flooring product is much more dimensionally stable than solid products, and can often be installed in a basement and over concrete.

FSC
Refers to the Forest Stewardship Council, an international organization that sets high standards for holistically preserving our world’s forests. The FSC addresses more than just flora and fauna, but also socio-economic factors, and respect for indigenous peoples’ rights in each individual country. FSC certification ensures that the product comes from a responsible and renewable source, and is the only certification for wood flooing currently accepted for LEED projects.

Gloss
Refers to how “shiny” a finish appears. Gloss levels are defined as a percentage; matte finishes having a low percentage of gloss, and mirror-like finishes having a high percentage of gloss.

Grading
Refers to the allowance of natural character marks, such as knots and mineral streaks, in a wood product. Consistent and accurate grading is critical to achieving the desired aesthetic in a wood floor.

Clear Grade
Refers to a wood flooring product that has been selected for near 100% heartwood content, and exhibits an absolute minimum occurrence of knots and mineral streaks. Some exceptions are made for certain species.

Select Grade
Refers to a wood flooring product that has been selected for a minimal occurrence of knots and mineral streaks, but may include sapwood.

Common Grade
Refers to a wood flooring product that exhibits a full range of natural character. Sapwood and heartwood are both allowed in this grade, along with full range of knots and mineral streaks. This grade is sub-divided into #1 Common and #2 Common, the former exhibiting less character and closed knots, and the latter exhibiting more character and open knots.

Rustic Grade
Refers to a wood flooring product that exhibits a full range of natural character, and in some species, allows the occurrence of holes through the pieces of flooring. In exotic species, this generally indicates high sapwood content and filled knots.

Grain
Refers to the direction, size, arrangement, appearance, or quality of the wood fibers.

Open Grain
Refers to the size of the wood pores. Open grained woods have larger pores, and therefore are easy to stain. Open Grained woods are generally softer than closed grained woods.

Close Grain
Refers to the size of the wood pores. Close grained woods have smaller pores, and therefore can be difficult to stain. Close grained woods are generally harder than open grained woods.

Green Building
Refers to the construction of energy efficient buildings with minimal impacts on human health and the environment. Some buildings can be more “green” than others. Therefore, certification systems have been established to benchmark these building projects. LEED certification has been established by the US Green Building Council (USGBC) for commercial projects. The Green Building Initiative (GBI), was started by the National Association of Home Builders (NAHB) and the International Code Council (ICC), to establish guidelines for residential construction, and to support those established in the LEED program. For additional infomation, visit our Green Building Information Page.

Heartwood
Refers to the older, non-living wood found at the core of a tree, which serves the sole function of support. Heartwood is usually darker and more durable than the surrounding sapwood.

Janka
Refers to a unit of measurement used to describe the surface hardness of wood flooring. A Janka rating is determined by the amount of force required to drive a 0.444 inch steel ball half its diameter into the wood product. Northern Red Oak (1290 Janka), is the gold standard against which all other wood flooring products are compared. Also see The Janka Scale of Hardness.

Knot
Refers to a roughly circular, and usually darker imperfection found in wood. Knots naturally formed in trees where side branches sprout from the tree trunk.

LEED
Refers to the Leadership in Energy and Environmental Design program, which was established by the US Green Building Council (USGBC) to benchmark design, construction, and performance of commercial buildings. Most architectural firms strive for LEED certification on their commercial projects, and many make best efforts to apply these standards to their residential projects as well. Currently, only FSC certified wood flooring is accepted towards “points” in LEED certified projects.

LEED AP
Refers to a LEED Accredited Professional; i.e. a person that has demonstrated a thorough understanding of green building practices and principles and the LEED Rating System.

Microbevel
Refers to a small (less than 1mm) 45 degree beveled edge cut. Microbevels are often used on prefinished wood flooring products. Since prefinished wood floors cannot be sanded for uniformity when installed, small variances in face height of each plank can cause things to “snag” on a raised edge. The microbevel helps compensate for these slight irregularities by essentially taking the “sharpness” away from any raised edges that may exist.

Millwork
Refers to manufactured wood products. As it applies to wood flooring, the quality of millwork is assessed by how well the pieces of flooring fit together: the amount of gapping between boards, consistency of face height, and the amount of sanding required when installing unfinished product.

Mineral Streak
Refers to a blackish or brownish discoloration running parallel to the wood grain. Mineral streaks naturally occur as minerals, which are extracted from the soil, accumulate in the tree by sap flow.

Mountain Grade
See Rustic Grade

Movement
See Dimensional Stability

NOFMA
Refers to the National Oak Flooring Manufacturers Association which more recently, began calling itself “The Wood Flooring Manufacturers Association”. This organization sets high grading and milling standards against which most wood flooring products are compared. NOFMA certification ensures that the product is graded and milled to a high level of quality – grading is consistent, pieces fit together snugly, there is minimal gapping between boards, and face height is consistent (minimal sanding required on unfinished floors).

Plainsawn
Refers to wood that is first cut on a tangent to the log, and all subsequent cuts are then made parallel to the first. This is the most common cut of wood used for flooring; it the least labor and materials intensive of all cutting methods, and yields the widest boards. Plainsawn products exhibit grain orientation in all directions.

Prefinished
Refers to wood flooring products with a factory-applied finish. Prefinished wood flooring is installed much easier and quicker than unfinished flooring. Prefinished floors often feature a microbevel or an eased edge to compensate for the fact that these floors cannot be sanded for uniformity during installation.

The modern factory finishes used on these products are more durable than site-applied finishes. Many different types of factory finishes are in use today, most of which are urethane based. The most modern prefinished wood floors feature multiple base coats of aluminum-oxide, urethane mid layers, and hard anti-scratch top layers. These modern finishes can be screened and recoated.

Quartersawn
Refers to wood that is cut at a perpendicular to the grain. Quartersawn flooring exhibits less gapping between planks during humidity swings due to the fact that expansion and contraction occurs on a perpendicular to the floor. Quartersawn products are more labor and materials intensive to produce, therefore quartersawn products carry a higher price than their plainsawn counterparts. Quartersawn products are often sold concurrently with riftsawn product.

Reclaimed
Refers to material that has been salvaged from an existing building for reuse. Often, reclaimed materials undergo some remanufacturing to make them more suitable for reuse in construction.

Riftsawn
Refers to wood that is cut at a semi-perpendicular to the grain. Riftsawn flooring exhibits less gapping between planks during humidity swings due to the fact that expansion and contraction occurs on a semi-perpendicular to the floor. Riftsawn products are more labor and materials intensive to produce, therefore riftsawn products carry a higher price than their plainsawn counterparts. Riftsawn products are often sold concurrently with quartersawn product.

Sapwood
Refers to the softer live wood that grows on the outer portion of the tree, just under the bark. The sapwood is responsible for managing sap and mineral flow, and ultimately for the growth of the tree. Sapwood is usually lighter in color and softer than heartwood.

Screen and Recoat
Refers to a maintenance procedure done to “renew” a dull or worn finish on a wood floor. The process involves lightly sanding the surface of a wood floor, and applying a fresh coat of urethane over the freshly sanded floor.

SFI
Refers to the Sustainable Forestry Initiative, a US-based organization that sets high standards for “wise use” of our forests. The SFI is responsible, in part, for the fact that there are many more trees in todays forests than in the mid-1900’s. SFI certification ensures that the product comes from a responsible and renewable source.

Solid
Refers to a wood flooring product milled from one solid piece of wood. Solid wood flooring generally should not be installed in a basement or over concrete.

Square Edge
Refers to a sharp 90 degree edge cut. Square edges are most commonly used on unfinished flooring products which will be sanded after installation for uniformity. Most prefinished wood flooring products feature a microbevel or eased edge.

Swedish Finish
See Acid-Cure Urethane

Tongue and Groove (T&G)
Refers to “tab and slot” features cut into the edges of a wood product. T&G construction allows for easy assembly and allows nails to be hidden from view once the flooring has been installed. This product feature also helps keep a floor uniformly flat once it is in service. Nearly all modern wood flooring features T&G construction on the long edges; many products also feature a T&G groove on the short ends as well.

Unfinished
Refers to wood flooring products that are intended to be finished at the job site, after installation. Unfinished wood flooring is more complicated to install than prefinished product, and requires much more time to complete the job. Because most unfinished products feature a square edge, the floor ultimately appears more uniform. Many people believe that these site-finished floors have a more elegant appeal because of their uniformity, and because many site-applied finishes also enhance the woods’ color and grain.

Urethane
Refers to polyurethane: a clear, elastic, petroleum based varnish commonly used to prefinish products at the factory, as well on unfinished products at the job site. In modern times, urethanes are modified with additives to affect drying time, durability, and clarity. Currently, aluminum oxide modified urethanes are one of the most common varnishes used on prefinished product. Respectively, oil-modified urethanes are the most commonly used site applied finishes; acid cure urethane (Swedish Finish), moisture cure urethane, and water-based urethane are also used on today’s unfinished floors.

Acid Cure Urethane (Swedish Finish)
Refers to a durable, non-yellowing site-applied finish. This type of finish dries by off-gassing heavy VOCs, and should be only used by professionals.

Moisture Cure Urethane
Refers to a very durable, non-yellowing site-applied finish, that has more moisture resistance than other types of finishes. Moisture cure urethanes dry by off-gassing heavy VOCs, and are difficult to apply. Therefore, this type of finish should be applied only by professionals.

Oil-Modified Urethane
Refers to the most commonly used site-applied finish. Oil-modified urethane is very easy to apply on most unfinished wood products, usually dries within eight hours, and ambers with age.

Water-Based Urethane
Refers to a durable, non-yellowing site-applied finish. This type of finish dries by water evaporation in about three hours, and releases comparatively few VOCs in the process. While water-based urethanes are more expensive, they are the only option for site-finishing some exotic species of wood.

Volatile Organic Compounds (VOCs)
Refers to chemicals that are emitted as gasses from certain solids or liquids, commonly referred to as “fumes”. Some VOCs can have short- and/or long-term adverse health effects.

Wax Finish
Refers to the oldest method of site-finishing unfinished flooring products. This finish is applied and maintained in thin layers which are then buffed, much like waxing a car. While this type of finish is easiest to apply and maintain, it does not protect the wood from wear.