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Hardwood Flooring Glossary




Above Grade

Refers to flooring installed above ground level, with a minimum of 18 inches of well-ventilated space available.


Refers to the act of wearing away at a hardwood floor finish, thereby damaging the wood.


Refers to the hardwood’s adjustment to the environment it is in, in terms of moisture and humidity.

Acrylic-Impregnated Flooring

Refers to flooring which has had liquid acrylic (and stain) injected into and throughout the surface of the flooring to add more durability.


is a clear wood finish known for its ease of use, fast drying times, and low odor.

Aluminum Oxide

is an amphoteric oxide of aluminum, commonly used to finish flooring because of its strength. Second in hardness to diamond, it serves as a hard protective coating for many hardwoods and bamboo.

Antique Flooring

uses older wood recycled from buildings to manufacture the flooring. Or, is distressed either by hand or machine to create an antique look.


is an acronym used for the American Standard Testing Methods.



Baby Threshold

Refers to a type of molding used in areas where expansion is needed, such as by sliding glass doors and to transition to carpet.


Refers to the molding installed at the base of a wall designed to cover a portion of the wall and floor. It is typically seen as quarter round, though other styles are available.

Base Shoe

Refers to a type of molding designed to attach to base molding to cover any expansion space.

Bastard Sawn

See “Rift Sawn”.

Below Grade

Refers to flooring installed in below ground areas such as the basement of a home. Solid hardwood cannot be installed below grade, whereas engineered hardwood can be installed below grade.

Beveled Edge

Refers to a type of edge available in hardwood flooring. With a distinct and deep “v” shaped groove, the beveled edge hardwood is commonly used in informal settings. Also used where subflooring imperfections exist, as it helps to conceal them as well as slight differences in plank thicknesses.

Bi-Level Reducer

is a type of molding used to transition from a hardwood floor to a carpeted room.

Blind Nailing

Refers to the process of forcing nails into the grooves of tongue and groove flooring planks. The nail is put in at a 45 degree angle and made flush by using an electric flooring hammer because most types of wood flooring, including bamboo, are too hard to be nailed together by hand.


Refers to a design technique when installing a hardwood floor that includes a pattern around the outside of the hardwood flooring. These borders can be simple or complex, and even premade.


Refers to warped and weakened hardwood as a result of conditions such as excessive moisture.

Bull Nose

Refers to a type of trim installed on a wall.


Refers to a swirl or twist of the grain of the wood that generally happens close a knot, but does not contain a knot.

Butt Joint

Refers to a type of joint made by forcing two ends together. Though it is the simplest type of joint to make, it is also considered the weakest because there is no support other than glue to hold the joint together.



Ceramic Finish

Refers to a more advanced finishing technology using ceramics to increase abrasion resistance of the hardwood.

Chatter Marks

Refers to patterned markings on the floor caused by the use of a drum sander.

Conversion-Varnish Sealers

Refers to a type of sealer that is acid curing and resistant to stain and spotting.

Cross-Ply Construction

Refers to engineered hardwood planks stacked on top of each other, in alternating directions, creating dimensionally stable flooring less affected by moisture and changes in humidity.


Refers to a type of warping where the center is higher than the sides.


Refers to warping where the sides are higher than the center.

Cutting Method

Usually refers to how the solid hardwood veneer for an engineered floor is cut. There are three cutting methods: dry solid-sawn, rotary-peeled and sliced-peel.

Wood Veneer Sawing Methods


The action of allowing the finish to completely dry and reach its fullest hardness potential. Different finishes will cure at different rates.



Dimensional Stability

The ability of the hardwood to retain its dimensions throughout its lifetime, avoiding warping, swelling and contracting in response to moisture and changes in temperature and humidity. High dimensional stability means the floor does not significantly warp, shrink or expand due to environmental changes.

Distressed Hardwood Flooring

Refers to the intentional scratching, scraping and/or gouging of a flooring surface to create an antique look. This is accomplished either through hand scraping or by machine. Floors that are distressed by hand will be unique – no two floors will be alike. Floors distressed by machine will likely have a repetition of pattern which may take away from the natural look of the floor. This flooring will add seasoned character to an interior and can easily hide finger marks and scratches, which is an excellent choice for high traffic areas.

Drum Sander

A type of sander used to smooth the surface of hardwood before finishing, known to leave chatter marks.

Dry Solid-Sawn

A cutting method for the real hardwood veneer that is glued on the top of engineered hardwood flooring. It involves letting the wood dry out slowly with a low humidity level to keep moisture from inside the wood cells intact, reducing the risk of cupping. It is the most expensive type of veneer for engineered flooring. It produces a veneer that resembles solid hardwood and generally costs more than other cutting methods.

involves letting the wood dry out slowly with a low humidity level to keep moisture from inside the wood cells intact, reducing the risk of cupping. It is the most expensive type of engineered flooring, but looks and acts more like a solid.



Eased Edge

Refers to a type of edge available in hardwood flooring which is slightly shallower than a beveled edge and slightly rounded versus “v”-shaped.

Edge gaps

Distance to the wall, which has to be observed when laying hardwood flooring. The so-called elasticity joint ensures that the floor can contract or extract when climatic changes occur. The distance to the wall should be minimum 8 mm which should also be observed when heating pipes, door frames, or pillars etc. are involved.

Edge Type

Refers to the edge of the sides of the strips or planks. Square edge has squared edges. Beveled, eased, micro beveled and micro beveled edges have a “v”-shaped groove which help to hide imperfections in the subfloor as well as slight differences in plank thicknesses.

Emission classification

A term, which is very often used in product information. E1 means that the formaldehyde emission limit decreed by law of 0.1 ppm (= 0.12 mg/m3 air) is observed.

End Cap/Molding

See “Baby Threshold”.

End Joint

See “Butt Joint”.

Engineered Hardwood

Wood made of a thin layer of solid hardwood glued or laminated onto a core board such as plywood or high density fiberboard to make the planks of flooring. Due to its construction, engineered hardwood is more dimensionally stable than solid hardwood and can be installed below grade and over a concrete subfloor.

Engineered Hardwood Flooring

Engineered Hardwood Flooring

Environmentally friendliness

Refers to the factors about hardwood–or any other product–that make it easy on the environment.

Exotic Species

Refers to the species of wood found outside of North America. These are typically more expensive due to their more limited availability.


Changes in dimension due to swelling and contracting of the flooring as a result of moisture.

Expansion Gap

Area of perimeter left to account for expansion.

Expansion Spacing

The amount of space left at the baseboard to allow for expansion.



Face Nail

Refers to a nailing technique that secures flooring to the sub-flooring by using nails perpendicular to the surface of the floor.


Refers to the wax based or urethane coating over hardwood flooring.


Refers to wood cut in long planks where the rings run parallel to the board. Also referred to as plain-sawn.

Floating Floor

A type of installation that does not require the flooring to be attached to the subfloor.

Flush Reducer

Used to level the height between a wood floor and another floor surface to transition from room to room.

Flush Stair Nose

Allows a smooth transition between the stair edge and the riser.

French Bleed

Stained edges of hardwood floor planks.

French Bleed Edge Hardwood Floor

French Bleed Edge Hardwood Floor



Gloss Level

Refers to the reflection from the finish. Standard gloss levels are satin or matte, semi gloss and high gloss.

Gloss Meter

A device used to measure the gloss level of a floor’s finish.

Glueless Click-Lock

Refers to a very easy do-it-yourself installation of engineered hardwood flooring. No glue is required to install the floor because everything “clicks” and “locks” into place.

Glueless Locking Engineered Hardwood

Glueless Locking Engineered Hardwood


Refers to the appearance of wood used to create the flooring, usually based on the number of visible knots and mineral streaks.


Refers to the alignment of the fibers in the wood, which designates the pattern seen on the flooring.



Hand Scraped Hardwood

Historically, floors were hand scraped on site to make the floors flat. Today’s hand scraping is usually done at the factory to give the floor an antique or vintage look. A truly hand scraped floor will be unique – no two hand scraped floors will look the same.

Hand Scraped Hardwood Floor

Hand Scraped Hardwood Floor

Hand Sculpted Hardwood

Similar to hand scraped hardwood, but a less distressed result.


The older, nonliving central wood of a tree or woody plant. Its cells usually contain tannins or other substances that make it darker and harder than the younger, surrounding sapwood. Heartwood is mechanically strong, resistant to decay, and less easily penetrated by wood-preservative chemicals than sapwood.


Hardwood installed parquet style to create a herringbone pattern.

Herringbone Parquet Wood Floor

Herringbone Parquet Wood Floor

High-density Fiberboard (HDF)

A type of core board used to make engineered hardwood. It provides more dimensional stability than plywood. It is made by compressing fibers of wood chips with an adhesive or binder at a high temperature.


The amount of water vapor in the air.


Device used to measure relative humidity.



Impact Resistance

The ability of a flooring material to resist fracture or damage from a falling object is termed as its impact resistance.

Inflammability classification

Refers to the likelihood that the flooring will not burn.

In-Floor Radiant Heating

See Radiant Heating.


Technique involving laying multiple pieces down to create a pattern inside the hardwood. For example, a border or a mosaic.

Installation Methods

Refers to the methods used to install hardwood flooring. Options include: nail down, glue down, staple down, and floating.



Janka Hardness

Refers to the strength of the hardwood material based on a scale which determines the amount of force it takes to drive a .444 inch steel ball into a plank of wood .222 inches in diameter.


A parallel beam used to support flooring or ceiling weight loads.



Kiln Dried

Wood dried with artificial heat in a controlled environment as opposed to naturally air dried.


The dark marking where the branch jointed the tree trunk.




A varnish that dries by solvent evaporation.




Stands for Material Safety Data Sheet, a required sheet that lists any hazardous ingredients, safety precautions, and first aid information that a consumer should know about a product.


A design or image meant to be inlaid into a hardwood floor.

Micro Bevel Edge

Refers to a type of edge available in hardwood flooring which is similar to a beveled edge, but has a shallower “v”-shaped groove than both the beveled edge and the eased edge. It is well suited for helping to hide minor irregularities in the subfloor, such as uneven plank heights.

Hardwood w/ Micro Bevel Edge

Hardwood w/ Micro Bevel Edge

Micron Bevel Edge

Refers to a type of edge available in hardwood flooring which is similar to a micro beveled edge, but with a shallower “v”-shaped groove. It can be difficult to distinguish from a micro beveled edge.

Mineral Streak

Mineral matter left in wood by sap, usually from injury during growth.

Mixed Media

Wood flooring that also includes other elements such as slate or stone.

Moisture Barrier

See “Vapor Barrier”.

Moisture Content

The amount of moisture in wood. Wood is hygroscopic, meaning it gains or loses moisture until it is in equilibrium with the humidity and temperature of the air. This is why it is important for wood flooring to acclimate before it is installed.

Moisture-cured Urethane

A finish which requires moisture in the air before it can cure.


There are a number of different types of moldings (aka trim and transition pieces) that are installed to give a flooring project a finished look.



Nail Down

An installation method requiring nails to attach the wood flooring to the subfloor.

Natural Stain

A clear finish that does not color the wood, but instead allows for the natural look of the wood to show.


An acronym for the National Wood Flooring Association.



Oil-modified Urethane

Most common finish for wood flooring, available in various gloss levels.

Oil-Treated Finish

An oil based finish for hardwood flooring.

On Grade

Refers to the ground level of a building as it is at the same level as the surrounding ground.

One-Sided Reducer

Has one sloped side and one flushed side and is used to transition from hardwood to other flooring types.


An acronym used to describe oriented strand board, a type of subflooring material.

Overlap Reducer

Used to transition between hardwood and carpet.

Overlap Stair Nose

Function as the finishing transition for the edge of a stair on a floating floor system.

Oxalic Acid

A poisonous strong acid that occurs in various plants as oxalates and is used especially as a bleaching or cleaning agent and in making dyes. One of the strongest organic acids. Other chemical or common names include Dibasic acid; Ethanedioic acid; Acid of sugar.



Parquet Floor

A floor that is installed in a manner that creates a geometric pattern, such as a herringbone pattern.

Parquet Hardwood Floor

Parquet Hardwood Floor


A building material manufactured from with wood fragments, such as chips or shavings, mechanically pressed into a sheet and bonded together with resin.

Paste Wax

Used to finish floors before the arrival of lacquers and varnishes. Since it never dries to a hard finish, it does not provide great damage protection, but can be used as polish to keep floors shiny and reduce the appearance of scratches. It will make the surface more slippery and may help prevent further scratches as objects can slide across the surface.

Penetrating Oil Sealers

These oil based sealers are spread across the floor, allowing them to penetrate the surface, offering a stain and a finish to protect it. Excess is removed with a sponge or cloth. They are usually comprised of tung or linseed oil.

Penetrating Sealers

As with penetrating oil sealers, without the use of oil.

Penetrating-Seal-Treated Finish

A finish that’s been treated with a sealer, applied by penetration into the floor.

Photo Sensitivity

Refers to the likelihood a wood floor’s color will change as it is exposed to light.

Pilot Hole

A small hole drilled into a material to assist in making the larger hole the right width.

Pin Knot

A knot no larger than ½ inch in diameter.


Making a series of parallel cuts into a log. This is known as the easiest way to make wood planks. Also referred to as flat-sawn.

Plank Flooring

Boards that are 3 inches wide or more.


Thin sheets of wood bonded together with adhesive to form plywood.


Dowels designed to mimic the Colonial “plugged” look.


Wooden material made by pressing together plies, or thin sheets of wood.

Pneumatic Nailer

A power nailer that uses air pressure to operate, commonly used to speed the process of nail down hardwood installations.


Type of finish for hardwood that does not require waxing.


Flooring that is stained and sealed before installation, usually done at the flooring factory.



Quarter Round

A type of trim used for vertical walls and the floor.


The log used to create wood floor planks is first cut into quarters and then cut into boards using parallel cuts.



Radiant Heating

A heating system installed below the flooring designed to improve energy efficiency in the home and keep the floors a comfortable temperature.

Random Length

Some flooring is sold as random length, meaning that the boards are not all the same length. The shortest length and longest length are noted, and all other planks in the box are different lengths that fall between those two numbers. For example, a manufacturer may describe their flooring as random length 12″-48″.

Random Width

Some flooring is sold as random width, meaning the boards are not all the same width. Typically, the each box of random width flooring is comprised of boards of 3 or more different widths. This creates a more traditional looking floor. Historically, floors were laid with random width boards so as not to waste any of the wood from the log. This vintage look is easily re-created today with random width boards.

Reclaimed Wood

Wood that is salvaged from an old building or structure or from a lake or river and refinished for use in another project.


See Screen & Recoat.


Used to join wood floors to other flooring surfaces.


Refers to the practice of sanding down a wood floor and finishing it again, to reduce the appearance of damage, wear, and tear. A solid wood floor can be sanded and refinished many times. However, an engineered wood floor can only be sanded and refinished if the veneer is 2mm or thicker.


Replacing sections of hardwood with new material to avoid having to sand and refinish the entire floor.

Resistance to staining

Allows an insight as to how the wood flooring will resist staining when subjected to a number of potential staining agents.


A method of cutting a log into boards that ensures each board has the same relation to the log, providing the same grain pattern. This is the most stable lumber. Also referred to as Bastard Sawn.

Rotary-Peel Cut

Refers to a cutting method used to create a solid hardwood veneer for the top layer of an engineered hardwood floor. It involves boiling the log for a certain amount of time at a certain temperature to prepare the wood. After the wood has been prepared, it is scraped from the log with a blade working from the outside in and then pressed flat. It typically has a plywood-like grain and can have issues with cupping and warping to try to revert to its original shape.




Refers to the wood near the outside of a tree. Usually softer and lighter in color than heartwood.

Scratch resistance

Allows an insight how the laminate flooring will behave, when scratched. This is a very important quality criterion, which is derived from scratching the flooring with a diamond tipped instrument.

Screen & Recoat

The practice of adding another top coat of polyurethane to improve appearance of the floor, after abrading it slightly (using a mesh screen) so that the finish adheres better.

Sheen Level

See “Gloss Level”.


A resin substance secreted by female lac bugs. Used to form a cocoon, the resin comes from India and Thailand. Processed as dry flakes, it can be added to denatured alcohol to create a liquid. This liquid is then used as a food glaze or floor finish. It’s a natural option which is highly resistant to stain and odor. It is a high gloss finish.

Shoe Molding

A type of molding that is humidity resistant and ideal for high traffic areas in a home.

Site Finished

The opposite of prefinished, unfinished hardwood is installed and then finished on site.

Sliced-Peel Cut

Refers to a cutting method used to create a solid hardwood veneer for the top layer of an engineered hardwood floor. It involves boiling the log for a certain amount of time at a certain temperature to prepare the wood. After the wood has been prepared, it is sliced from the end and then pressed to create a veneer.

Small Knot

A knot in the wood that is not over 1/2″ in diameter.

Solid Hardwood

One piece made from lumber, unlike engineered hardwoods which use other materials to form the planks.

Solid Hardwood Flooring

Solid Hardwood Flooring

Solvent Based Urethane

Uses an oil chemical base rather than water in the floor finish.

Sound Knot

A knot with an exposed section which appears elongated, as a result of a cut parallel to its long axis.


Refers to the type of wood, or the kind of tree it was harvested from. Many species are available such as oak, pine, cherry, and hazelnut.


Also known as “slip tongues” these are used to reverse or change the direction when installing tongue and groove hardwood flooring.

Square Edge

The edges of the floor boards flush together to decrease the appearance of lines between boards. This creates a uniform and smooth surface and gives the room a contemporary, formal feel.

Square Nose

Trim used along the walls of floating floors.


Coloration of flooring other than its natural color.

Stain Resistance

The degree to which a material resists permanent discoloration from exposure to household items, most notably liquids, is termed as stain resistance.

Stair Nose Molding

Used for transition when placing plank or strip on stairs, landings or step downs.

Strip Flooring

Thinner boards of wood, smaller than planks, 2 ¼” wide.


Support structure for walls and flooring.


A support surface below the flooring, such as plywood or concrete.

Surface-Sealed Finish

A finish which also serves to seal the wood to protect it, applied directly to the surface without penetration.

Swedish Finishes

See “Conversion-Varnish Sealers”.




Refers to a molding piece that finishes the space between two areas of wood.


Refers to how thick the planks of hardwood flooring are.

Thin Profile Solid

A thin piece of solid wood.


See “Baby Threshold”.

Tongue and Groove

Also known as T&G, this refers to the profile construction milled to the panels’ sides allowing the panels to interlock easily with one another. The connection of tongue and groove is responsible for stable floor construction and protects the floor from moisture.


Moldings used to transition from hardwood to another flooring type.


See “Moldings”.

Tung Oil

A type of oil used to finish wood. It is extracted from the seeds of the tung tree.




The layer of material that is laid loosely between the sub-floor and and the main flooring. It serves one or more of the following functions: vapor barrier, padding, sound barrier and/or insulation. Examples of underlayment include foam, rosin paper/felt, cork, plastic sheathing or Quiet Walk.

Unfinished Wood Floor

Flooring that has not been pre-finished at the factory, meaning it must be finished on site after installation.

Universal Edge

A transition used to join hardwood to carpet.


A chemical solvent used to seal and finish wood floors.


Cured with UV light rather than heat.



Vapor Barrier

A type of underlayment that protects the flooring from moisture coming from the subfloor (e.g. a concrete subfloor).


A finish containing oils with a slow curing time that can be decreased by heat.


A thin layer of real, solid hardwood glued to the top of a core board to create an engineered wood floor. Veneers can vary in thickness from 0.6mm to 6mm. Veneer thickness dictates how many times an engineered wood floor can be sanded and refinished. If the veneer thickness is less than 2mm then the floor cannot be sanded or refinished at all.



Wall Base

See “Baseboard”.


See “Buckle”.

Water Based Urethane

A solvent containing water in the formula.


See “Paste Wax”.

Wear Layer

See “Veneer”.


A cost effective finish option, a type of paint that takes a long time to cure.

Wire Brushed

A way to distress wood flooring by machine for an antique look.

Brushed Finish Hardwood Floor

Brushed Finish Hardwood Floor

Wood Movement

The expansion and contraction of wood due to moisture content which must be accounted for during installation.

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