What Are Some Common Wood Flooring Terms?

All fields and industries have a language that is particular to their own field; wood flooring is no exception.  What are some common terms which may not be immediately familiar?


The most common unfamiliar terms that apply to both solid wood and engineered wood flooring are site-finished (unfinished floor that must be stained and sealed on-site); pre-finished (wood flooring that comes with a thick, factory applied finish); and random bundle flooring (floor boards that range in length from several inches to several feet).


In alphabetical order, this is a partial list of terms:


The highest appearance and grade of wood. Clear means that the wood may have some minor characteristics, but only very minor. These characteristics might include tiny knots. Largely, the wood is considered to be as perfect as possible.

Close Grain (or Closed Grain)

Finely and closely arranged wood grain fibers.


The lowest grade and appearance; lower than clear or select. This type of wood has the most amount of knots, wormholes, flags, and other characteristics.


The quality of the wood: i.e., clear, select, or common.


The arrangement of the fibers of the wood.

Janka Hardness Test

A unit that indicates the force needed to embed a .444 inch steel ball halfway into the piece of wood being tested. The harder the wood, teh higher the number. For example, Brazilian Cherry is very strong, at a 2350 Janka; Douglas Fir is very soft at 660 Janka.

Nested Bundles

Nested bundles of wood flooring still have random lengths of floorboards, but they do not differ so wildly as the previous category.  Lengths here range from about six to eight feet.

Open Grain

Large pores and widely spaced fibers in the wood’s grain.


Wood flooring in widths of 4 inches or greater.


Fast becoming the norm, pre-finished wood floors are already sealed (usually with polyurethane) and in some cases, stained.

Random Bundles or Average Length Bundles

When you buy something called a random bundle, this refers to the length of the boards not the quality (though that may accidentally be the case, too).  With random bundles, the length may range from 8 or 9 inches…all the way up to 8 feet long.  Predictably, the lengths are more on the lower end of the range.


A lower grade and appearance than clear. Select may have some characteristics such as knots or wormholes. Note that, with the right type of wood, select characteristics can be considered a desirable mark of distinction rather than a defect.


Another word for unfinished wood.  This term emphasizes that the floor will be finished on-site, in the location of installation.


A fancy word for the type of wood: i.e., ash, beech, oak.

Specified-Length Bundles

This is a rare category.  It’s just the way it sounds:  every floorboard is the same, exact length (a couple of feet or shorter).  You probably won’t need specified-length bundles, unless you’re putting together some kind of patterned floor.


Wood flooring in the more common widths of 3 3/4″ or less.


An underlayment such as 3/4″ plywood that is installed directly on the joists and under the finish flooring.

Tongue and Groove

Found in strip. plank, or parquet flooring. On the edge of one piece of floor is a protruding piece called a “tongue.” On the edge of a different piece of floor is a cavity into which the tongue will lock. This cavity is called the “groove.” It is similar to the way a Zip-Loc bag works.


Essentially, raw wood with no type of stain or sealant. You will need to seal before using.




Leave a Reply