What is wood grading?

When it comes to hardwood flooring, the term “grading” refers to the system used by manufacturers to assess the appearance of the wood. The Wood Flooring Manufacturers Association grades emphasise colour, grain pattern and other markings that occur naturally in wood.

When choosing your new flooring you need to be aware that there are a variety of wood grades available, and that each of these grades will give your floor a slightly different look. The grade is based upon the type, number and location of visible defects found in a board of wood, and the process of grading allows you to have some control over the visual appearance of your flooring.

Grading

• Prime grade - only minor natural colour variation and small pin knots are allowed in prime grade wood. This lack of prominent grain colouring and knots will generally result in a much more uniform and consistent looking floor. This tends to be the most expensive grade of wood and is usually cut from the heart of the log where the wood has fewer rustic characteristics.
• Natural grade – somewhere in between prime and rustic grades, more of the natural characteristics of the wood are allowed in natural grade wood. Depending on the species of hardwood you may see some of the following characteristics in prime grade wood; small knots, streaks and grain patterns, with a limited amount of natural colour variation. Coloured wood filler is used to fill any naturally occurring holes or recesses in this grade to produce a completely smooth surface finish.
• Rustic grade - contains all of the characteristics that you would naturally find in hardwoods, including any level of natural colour variation, knots of all shapes and sizes, mineral streaks, checks, worm holes and grain burls. Again, coloured wood filler is used to fill any naturally occurring holes or recesses so that the wood has a smooth finish.

Colour

Colour is determined by what part of the tree the wood is cut from. Heartwood is the oldest, most dense, innermost section of the log, and is often darker and richer in colour than sapwood, which lies closest to the bark. The colour difference between the two can be so pronounced that heartwood and sapwood from the same species may even be sold under separate names.

Cut

The grain pattern of wood is determined by the species and how the wood is cut. Boards can be cut from a hardwood log in several directions; tangent to the annual rings (plain-sawn or flat-sawn), or radially across the rings (quarter-sawn and rift-sawn). Each will result in a different grain pattern and give the wood flooring a different character.