Hardwood Glossary

To deepen your understanding of the floor covering industry, rely on the hardwood brokers.

Janka Rating	The Janka rating is a numerical quotient that relates directly to the hardness of any given wood. Obtaining the Janka rating of the wood can be achieved through the Janka Hardness test, explained in the following piece. The relative hardness a species of wood possesses effectively shows how durable it will be.
Janka Hardness Test	The Janka Hardness Test is the method used to determine a species of wood's specific hardness. The method most commonly used is the depression in a wood to half the diameter of a steel ball exactly 11.28mm in diameter. This measurement was chosen so that the indented area is 100 square millimeters. The results will often vary in one piece of wood according to where the ball is pressed in relation to the grain of the mood. For example, against the face of a plank, it is considered a "side hardness" quotient, and therefore different from an "end hardness" quotient.
Wear Resistance	The wear resistance of a chosen floor product is proportionate to A.) the relative hardness of the wood – determined by the Janka Hardness Test and measured typically by pounds-force (lbf) on the united States – B.) the finish applied over the wood, if any. The more wear resistance on any given flooring product, the longer it will last in-use. Higher trafficked areas will be worn more quickly than less-traversed floors.
Hardwood	Hardwood is the term generally used to contrast softwood – explained elsewhere – however, the two do not necessarily reflect their names. For example, Balsa wood, a hardwood, is softer than many species of softwood. The terminology focuses more on the typical density ratings, which is higher in hardwood. Hardwood is the preferred flooring choice – whether solid or engineered – for floors that will be frequently crossed, due to the typical superior durability.
Softwood	Softwood is a type of wood harvested from coniferous trees, like Pine, that usually has a lesser density than hardwoods. Some softwood is technically harder than hardwoods, and therefore the two groups overlap in terms of durability.
Heartwood	Heartwood earns its name from its position in a tree. Past the outer layers of a tree lies the sapwood, and deeper in, the heartwood. It is normally darker in color, and is the oldest layer(s) of the tree's innards. Heartwood is normally sought after as a more rustic flooring product, displaying age and color in an almost exotic fashion.
Above Grade	To say a floor is above grade typically refers to its elevation in comparison to the structure's foundation. This means that a second story floor is above grade, while ground-level flooring is "On Level." In accordance, basement flooring is below grade.
Acrylic Impregnated	Acrylic impregnated floors are vacuum dried to remove moisture. After, they are then filled with a liquid acrylic that is often fire retardant in addition to color-stained. The implanted acrylic greatly increases the durability of the wood in floor uses, making it a preferred choice for many customers. Soaked through with the acrylic imparts a coloring that permeates well-through the entire wood, and can be used to identify acrylic impregnated wood from other types of flooring.
Acrylic Urethane	Acrylic Urethane is a compound that is used to finish flooring and other surfaces. It is resistant to stain and chemicals allowing for simple cleaning practices and very little maintenance.
Aluminum Oxide	Durability-enhancing Aluminum Oxide is a finish that is applied to hardwood floors to improve the lifespan of a wood in use. It is a likely choice for home use in finishing recently installed flooring.
Below Grade	Below Grade is the term used to represent a below ground-level surface, normally flooring. It can also be used to describe the foundation in which the flooring is place, I.E. the concrete setting of a basement.
Beveled Edge	A beveled edge is one that is often placed at a 45 degree angle, as opposed to the standard corner edge of 90 degrees.
Eased Edge	Eased Edges are round, if only partially. They are sometimes referred to as "lips" at the edge of a surface.
Square Edge	Squared edge flooring is in opposition to tongue-and-groove flooring, in that T&G uses interlocking patterns to link together, and squared edge does not. The edges have no indentations or protrusions, and slide next to a parallel piece smoothly.
Cross-ply Construction	Cross-play constructed engineered wood uses plywood strips under the veneer hardwood surface to form stability. It also protects against moisture. The plywood pieces are able to interact with each other, and therefore reduce the amount play caused by moisture.
Buckle	Buckling occurs from moisture causing expansion in the wood. This leads to cupping and buckling, and is a problem if there is no expansion space between the floor and the wall. Also, sanding should be avoided if buckling or cupping occurs, since it can lead to crowning.
Cupping	Cupping occurs when moisture trapped beneath the subfloor and the floor causes the wood expand, pushing together and causing the edges to raise with the next plank it is colliding with. Think of tectonic plates in the earth's crusts creating mountains. This example closely resembled the effect.
Bow	Bowing occurs when joists are bent under continuous weight of the floor above. The most common and simplest way to remedy this is to affix new, straight joists to the already existing ones.
Crowning	Crowning is the term used to signify small gaps in the surface of flooring after cupping. It is often a simple mistake made when cupping occurs. The raised edges of flooring pressing together – known as cupping – are sanded down. Eventually, when the wood dries, it retracts to its original size and shape, and leaves small recesses at the adjoining edges of floor planks.
Floating Floor Installation	A "Floating Floor" refers to flooring that does not follow the typical standards of being glued, stapled, or nailed to the subfloor. It instead uses stability enforced by its position in relation to the planks surrounding it in a singular level. An example would be puzzle pieces interlocking to hold their position. Methods vary, from snap-and-lock products, like laminates, to flooring that is glued plank-to-plank.
Graining	Graining refers to the pattern and texture of a wood. There are several general types of graining, such as straight grain – which as the name implies, travels one direction – and grains like the more complex Bird's eye and quilted. Different grains have different feels and levels of general smoothness. In woodworking – like the production of wood flooring – different methods are used to hone the wood's general appearance. Planing wood is one example and is often done with the grain. To "go against the grain" is a common saying that means one of two things: to fight against a force that is opposing you, or to simply be away from the norm. This is derived from the difficulty and choppy effects that planning against the grain can produce.
Knot	A knot is a dense formation of wood set into the graining. It is considered an imperfection for most, but has been known to accentuate certain types of wood with its usually darker appearance. It can be recognized as a sort of divergence point for the grain, separating the "flow" into two separate columns that break apart upon meeting the grain, and reconnect after it passes by.
Burl	A burl is a type of aberration in trees that forms when stress is induced, either from the environment, or by man. Most often, it is located beneath the ground in the root system, and will resemble bulbous growths. Similarly, above-ground burls are typically growth-like deformities that sprout from branches, and rarely, the trunks of trees. Burl wood is considered rare, and therefore prized by the more artistic crowds. The popularity, teamed with its inherent difficulty to woodwork make it a pricey choice. The erratic behavior of the grain is to blame for the difficulty in working the wood.
Long Strip Plank	Long strip planks are a version of floating floors that resembled engineered flooring. However, they are not exclusively floating, and can be glued, nailed, or even stapled down, making them ideal for certain subfloor types. Several layers of plywood make up the main portion of the plank, and are topped with a hardwood finish layer as the surface. The name itself is earned from the length of the plank, some eighty-six inches usually.
Moldings	Moldings are end-pieces, usually transitional pieces between one level of flooring to another. For example, lets say a small gap exists between your wall and the flooring. A molding would be used, more likely a square nose molding. Square nose moldings are also used to transition from two different level floorings, like tile and hardwood.
Nail Down	Nail down flooring refers to the process of nailing down hardwood planks. The task is best begun by hand ½" from the longest, most visible wall. After the third row, your options increase to nail guns like manual or pneumatic. As you near the end, you must switch back to hand nailed wood, and try to leave another 1/2" space between the end of the floor and the wall. This is to allow for expansion in the wood caused by moisture and temperature.
On-Grade	On grade refers to ground-level (or very nearly) ground level flooring.
Plank	A plank is the standard piece of hardwood flooring, being typically wider than strip flooring.
Strip	Strip hardwood is the thinner width flooring, contrasting with the wider plank flooring.
Polyurethane	Polyurethane has two common uses in flooring. The first is as part of the underlay beneath carpet. A foam polyurethane will increase the feel underfoot, and prolong the life of carpeting. The other typical use is as a protective finish on hardwood. A polyurethane coating will increase the wear resistance of the flooring and minimize damage to the floor itself.
Pre-Finished Wood Floor	Pre- finished wood flooring is pre-finished by the manufacturer.
Un-Finished Wood Floor	Un-finished wood floor can refer to wood floor that is not pre-finished by the manufacturer, or to flooring that has no protective finish.
Rotary Cut	Rotary cutting is the term used for "peeling" the wood away using a giant lathe. The process is mostly used to produce the thin layer of hardwood that tops engineered flooring. This method reveals wilder graining patterns.
Sliced Cut	Standard cut, as if lumber. This method shows fine grains.
Quartersawn	Quartersawn refers to how the wood was cut from the log. This particular method produces grain that is vertical instead of horizontal, which is called Plain sawn. Quartersawn is normally suggested for better stability than plainsawn.
Rift Sawn	Rift sawn wood shows clean, straight grains normally between 30 and 60 degrees to the face of the wood. Click to see a picture of rift sawn floors.
Tongue and Groove	Tongue and groove refers to the way two pieces of wood flooring join together. On one side of the wood, an indentation is present, and on the other, a small protrusion that fits into the next piece of wood's groove. The tongue is normally made just smaller than the groove so that fitting is guaranteed. This joining of wood encourages a single, flat surface.
Expansion Gap	An expansion gap is the small gap left between the end of a flooring project and the wall. Normally, 1/2in is left from wall to floor so when and if the heat expands from the effects of moisture and temperature it won't cause any damage to the wall.
Floating Reducer	Often referred to as an overlap reducer, this type of molding is intended for floating floors placed over a subfloor to allow for movement of the flooring. The idea is to transition between the upraised floating floor to the subfloor beneath smoothly.
Floating Stair Nose	With the bull-nose fitting, floating stair noses are used when the floor over stairs is floated, and allows for movement of the floor on the subfloor.
Subfloor	A subfloor is the layer of floor directly beneath the floor paneling. It is often concrete or even plywood. Some subfloors can be earlier-installed layers of hardwood floor or other flooring types, although in many cases, it is considered better to remove certain types of flooring before attempting to install new flooring.
T-molding	T-molding is used to transition between two different floors that are approximately the same thickness. It can be used to transition from wood to tile, like from a hallway to a bathroom.
Underlayment	Underlayment is designed to improve comfort underfoot as well as insulate against heat, moisture, and sound. By providing a soft layer underneath the floor, it allows for a small amount of malleability, thus improving the feel of hardwoods by reducing the stiff feel they can sometimes possess.
Wear Layer	The wear layer of a floor is best defined by the finish put over the flooring. It is considered the protective layer, and there are many different choices, from aluminum oxide, to polyurethane. It can come pre-finished with your flooring choice, or applied at home after installation. The more coats, the better protection you'll have. High-traffic areas normally merit more coats.
Board-foot	One board foot is the measurement used to define the measurements of wooden boards. There are many ways that it is expressed mathematically, but the constants are: one foot long, by one foot wide, with a one inch thickness.
Distressed	Stress is applied to flooring through usage. Everyday use or strenuous weight on it will cause the flooring to become distressed. The term is usually applied to flooring that has experienced much since installation, and it can be seen through dents, scuffs, and perhaps more significant damage marks.
Joist	Joists are support structures that run horizontally underneath the subfloor. They are more a part of the house's structure than of the actual floor, but are important to factor in when installing any flooring. The type, length, and depth of joists is important in deciding what type of flooring to use over what type of subfloor you have or intend to install. Joists run from wall to wall, wall to beam, or beam to beam, and are sometimes called girders.