Hardwood Glossary

For definitions of other terms not listed here, please go to these sections: How It’s Made, Styles, Before You Buy and Installation.

Above Grade
Any floor that is above the level of the surrounding ground on which the structure is built.

Acrylic Impregnated
Acrylic monomers are injected into the cell structure of the wood to give increased hardness and then finished with a wear layer over the wood.

Acrylic Urethane
A slightly different chemical make up than Polyurethane with the same benefits.

Aluminum Oxide
Added to the urethane finish for increased abrasion resistance of the wear layer, which is becoming extremely popular on the better grade wood floors.

Below Grade
A cement slab poured below the level of the surrounding terrain.

Better
A quality of oak. Better Oak has some small knots and very little dark graining.

Beveled Edge
These products have a very distinctive groove in them. Beveled edge planks lend themselves to an informal and country decor. With the urethane finishes applied at the factory today, the beveled edges are sealed completely, making dirt and grit easy to be swept or vacuumed out of the grooves.

Buckle
In the summer months, when the humidity is higher, wood will expand and gaps will disappear. If there is too much moisture it may cause the wood planks to cup, or buckle.

Ceramic
Advanced technology that allows the use of space-age ceramics to increase the abrasion resistance of the wear layer.

Clear
A quality of oak. Clear Oak has no visual blemishes or knots and is extremely expensive.

Cross-ply Construction
Engineered wood plies that are stacked on top of each other but in the opposite direction is called cross-ply construction. This creates a wood floor that is dimensionally stable and less affected by moisture than a 3/4” solid wood floor. Cross-ply construction allows the plies to counteract each other which will stop the plank from growing or shrinking with the changes in humidity. The other advantage for you is versatility. You can install these floors over concrete slabs in your basement as well as anywhere else in your home.

Cupping
A type of warping with a concave condition; the sides are higher than the center.

Eased Edge
Each board is just slightly beveled. Some manufacturers add an eased edge to both the length of the planks as well as the end joints. Eased edges are used to help hide minor irregularities, such as uneven plank heights. Eased edge is also called micro-beveled edge.

Engineered
One of the three common types of wood floors. (Others are Solid and Longstrip Plank.) Engineered wood floors are generally manufactured with 2,3, or 5 thin sheets or plies of wood that are laminated together to form one plank. Most engineered floors can be nailed down, stapled down, glued down, or floated over a wide variety of subfloors, including some types of existing flooring.

Finish in Place
Finish in Place, or unfinished hardwood, is installed in the home and then sanded. The stain and 2-3 coats of urethane finish are then applied. The urethane finish, brushed or mopped on, is known as a “floor finish” not a “furniture finish”. Finish in Place floors may be screened and recoated to rejuvenate the finish and revitalize the floor’s natural beauty.

Floating Floor Installation
With the floating installation method the floor is not mechanically fastened to any part of the subfloor. A thin pad is placed between the wood flooring and the subfloor. Then a recommended wood glue is applied in the tongue and groove of each plank to hold the planks together. The padding has its advantages: it protects against moisture, reduces noise transmission, is softer under foot, and provides for some additional "R" value. Some engineered floors and all Longstrip floors can be floated.

Glue Down
The recommended mastic or adhesive is spread on with the proper sized trowel to adhere the wood flooring to the subfloor. You should know that engineered wood floors and parquets can be glued down. Solid strip floors and plank floors can only be nailed or stapled.

Graining
Each wood species has its own unique graining and texture. The graining on the boards is determined by the way it has been cut. Natural variations in the color and grain are normal and to be expected.

Janka Hardness Test
This wood hardness rating test measures the force needed to embed a .444 inch steel ball to half its diameter in a piece of wood. The higher the number the harder the wood. Although this is one of the best methods to measure the ability of wood species to withstand indentations, it should be used as a general guide when comparing various species of wood flooring.

Knot
On a piece of wood, the round, harder, usually darker in color, cross section of where the branch joined the trunk of the tree.

Laminate
Laminate is a manufactured product that simulates the look of hardwood, ceramic tile, natural stone and many other types of flooring.

Long Strip Plank
One of the three common types of wood floors. (Others are Engineered and Solid.) Long Strip Plank floors are similar to Engineered floors and have several wood plies that are glued together. The center core is generally a softer wood material and is used to make the tongue and groove. A hardwood finish layer is glued on top of the core. The top layer can be almost any hardwood species and is made up of many smaller individual pieces that are laid in three rows. This gives the effect of installing a board that is 3 rows wide and several planks long. Long Strip floors come in a wide variety of domestic and exotic hardwood species and when damaged they are easy to replace.

Moisture Cured Urethane
A similar chemical make up as solvent-based urethanes, but this finish needs the humidity (moisture) in the air to cure.

Moldings
Are used to cover expansion joints and to enhance the performance and appearance of the hardwood floor. In many cases, moldings and baseboards need to be removed for hardwood installation.

Nail Down
This method is typically used with the 3/4" solid products, however there are adapters available for thinner flooring sizes as well. 2" nailing cleats are used with a wood flooring nailer and mallet to attach the flooring to the subfloor.

Number 1 Common
A quality of oak. Number 1 Common Oak has more knots and more dark graining.

Number 2 Common
A quality of oak. Number 2 Common Oak has more knots and more dark graining.

On-Grade
A cement slab that exists on the same plane as the surrounding terrain.

Plank
When shopping for a hardwood floor you will see boards in various sizes. The narrower board widths are referred to as “strips” and the wider units as “planks.” When we think of solid wood floors we generally are talking about a 3/4" thick plank that is 2 1/4" wide. This is the classic strip wood floor, although it is possible to find a narrower width or a slightly thinner gage. The strips are generally in random lengths from 12" – 84".

Polyurethane
A clear, tough and durable finish that is applied as a wear layer.

Pre-Finished Wood Floor
Pre-finished hardwood flooring comes ready for installation in your home. The hardwood boards have already been sanded, stained and finished at the manufacturing plant. In many cases this can provide a harder, better- protected surface. Several coats of urethane are sprayed on the boards and then they are UV dried for a very durable finish. Pre-finished floors offer a wider variety of wood species and save hours of labor and cleanup. They also may be screened and recoated to rejuvenate the finish and revitalize the floor’s natural beauty.

Rotary Cut
Each species has its own unique graining and texture. The graining on the boards is determined by the way it has been cut. Rotary Cut is a cutting process that displays a larger and bolder graining pattern. 

Select
A quality of oak. Select Oak has some small knots and very little dark graining.

Sliced Cut
Each species has its own unique graining and texture. The graining on the boards is determined by the way it has been cut. Sliced Cut is a cutting process that shows a more uniform pattern.

Solid
One of the three common types of wood floors. (Others are Engineered and Longstrip Plank.) Solid wood floors are one solid piece of wood that have tongue and groove sides. When we talk about solid wood floors, we tend to think of floors that are unfinished, but it’s important to know that there are also many pre-finished 3/4” solid wood floors. Solid wood floors are sensitive to moisture and because so they are used in nail down installations and are not recommended for installation below ground level, or directly over a concrete slab.

Solvent-Based Urethane
Oil is used as part of the chemical make up of the polyurethane finish.

Square Edge
The edges of all boards meet squarely creating a uniform, smooth surface that blends the floor together from board to board.

Stapled Down
With this method 1-1/2 to 2 inch staples are used versus nailing cleats to attach the wood flooring to the subfloor. A pneumatic gun is used to drive the staple into the wood flooring and subfloor.

Strip
When shopping for a hardwood floor you will see boards in various sizes. The narrower board widths are referred to as “strips” and the wider units as “planks.” When we think of solid wood floors we generally are talking about a 3/4" thick plank that is 2 1/4" wide. This is the classic strip wood floor, although it is possible to find a narrower width or a slightly thinner gage. The strips are generally in random lengths from 12" – 84". The most common wood species used for solid strip floors are red oak, white oak, maple, cherry, white ash, hickory or pecan.

Tongue and Groove
The joining of two boards, one board having a tongue on its edge that fits into a groove in the edge of the other.

Trim
See Moldings.

Un-Finished Wood Floor
An Un-Finished wood floor allows you to have a custom job – you choose the wood species and it’s sanded and the stain is applied on site. With Un-Finished you also have the chance to level the surface of the entire floor after it has been installed.

UV Cured
Factory wood finishes that are cured with Ultra Violet lights versus heat.

Water-Based Urethane
Water is used as part of the chemical make up of the polyurethane finish.