Following National Wood Flooring Association’s (NWFA) guidelines, unfinished domestic hardwoods, such as White Oak, Red Oak, and Hickory, are graded on appearance. Prefinished hardwood, on the other hand, is based on a manufacturer’s descriptions, which are mostly for marketing.

When you are looking to buy unfinished wood flooring, your hardwood floor will be categorized into one of the following grades:

• Clear – Has a uniform appearance primarily composed of heartwood.
• Select – Almost as uniform as Clear but with some natural characteristics.
• #1 Common – Has more color variety, some mineral streaks, and knots.
• #2 Common – Greater color variation and natural marks.
• #3 Common – Value flooring with distinct natural marks.

Maple is an exception. If you want to add unfinished maple hardwood to your home or building, a similar range of quality is described by the following terms: First, Second, and Third. Contemporary terms Select #1 and Select #2 may be used instead.