Understanding Wood Grades

Hardwood Flooring: Understanding Wood Grades

If you’ve been shopping around for hardwood flooring, you may have come across the term “grade” and wondered how a wood’s grade will affect the overall quality of the flooring you choose.

Actually, grade and quality are two separate measures that when combined will help determine a product’s value. Grade can be best described as the visual look of the natural wood. Grade is evaluated along a wide spectrum that ranges from very uniform in appearance, without knots or other standout characteristics, to significant color variations, short lengths, open knots, streaks, shake, worm holes, wane, and other woodworker-specific terminology used to describe wood’s natural features.

Quality, on the other hand, is manufacturing related. So while grade is “what the tree gave you to work with,” how that natural wood is manufactured to create the final planks plays another key role in the overall value of the flooring. For instance, a high-grade wood may have manufacturing defects, which would lower the flooring’s “quality” and overall value. Conversely, a low-grade wood may have little to no manufacturing defects, which would increase its quality and thus raise its value. For this very reason, product warranties are almost always tied to quality and are less dependent on a wood’s grade.

Furthermore, when it comes to grade, one size does NOT always fit all. This is because no two tree species are exactly the same. For example, a wood such as Maple, which characteristically has clean lines and light coloring, will be almost white in appearance at its highest grade. Whereas, a wood such as Hickory, which is characterized by active grain patterns and dramatic board-to-board color variations, will never look as “clean” as Maple, even at its highest grade.

Making the Grade – What It All Means

Within each species of wood, the highest grades will be the ones that are the most uniform in color and have the longest board lengths. The industry standard is 7’ lengths, but longer lengths of up to 10’ are gaining in popularity, in addition to ultra-long lengths. The lowest grades, which are oftentimes the least costly, will include far more color variations between boards and much shorter board lengths with the average ranging from 8 to 24 inches long. A grading system is used for both Prefinished and Unfinished hardwoods. While the descriptions within each grading category are fairly similar for prefinished and unfinished woods, the terminology used to refer to these grades may be different depending on the manufacturer.

Following is a table that lists these grades, along with a brief description of the characteristics and allowable defects found within each. Keep in mind that unless specified, the allowable defects listed are considered part of the industry’s standard 5% waste factor allowed for all better wood flooring grades (this can be as much as15%-20% for low grades).

Wood Grades: Characteristics and Allowable Defects

Prefinished Wood Grades Unfinished Wood Grades Wood Characteristics Allowable Defects
Prime/A Grade/Clear Grade Clear Grade/1st Grade/Select & Better These boards represent the top grade within each wood species. Woods are cut from the center of the log and have a highly uniform appearance with few knots. The sap content of this wood is low, and color variations are minimal. After finishing, the face of the boards will have the “cleanest” appearance of that species.
  • Natural color variations
  • Off-color streaks not more 6” in length or the equivalent
  • Occasional small burls, very small tight knots, and fine pinworm holes – in limited pieces and properly filled
  • No pieces with less than a 3⁄4” full tongue
  • Includes boards with the longest plank lengths
Standard/B Grade/Select/ #1 Common & Better Select/2nd Grade/ No. 1 Common/Common & Better These boards represent the next-best wood flooring grade. While the face of these boards contains more wood characteristics relevant to the species, the face is still even and smooth after filling and finishing.
  • Small worm holes
  • Season and kiln checks
  • Dime-size broken knots
  • Larger open knots, if properly filled and finished
  • Other limited small unfinished/unfilled open characteristics
  • Minor imperfections from machining
  • Some sapwood, torn grains, and burns
  • Other characteristics that will not impair the soundness of the floor
Note: Large grub worm holes, splits extending through the plank, and similar defects are NOT allowed.
#2 Common / C Grade / Builder/Mill Run / Character / Rustic /Sapwood/ Natural / Shorts #2 Common / C Grade / Builder /Mill Run/ Character / Rustic /Sapwood/ Natural / Shorts Boards within these grades include most of the wood’s spectrum of natural character. Woods include more color, bigger knots, and creamy-colored sapwood. A limited amount of unfilled or unfinished open characteristics on the face are also allowed. Also expect to find overall shorter pieces. Note: Characteristics that are NOT allowable for these grades include:
  • Mismanufactured boards
  • Shattered or rotten ends
  • Large open knots
  • Pieces with less than a 1⁄4” full tongue
  • Any other unsound defects
Allowable defects include a limited amount of pieces with some finish irregularities, including:
  • Bubbles
  • Small skips
  • Lines
  • Stain or color variations
  • Surface handling scratches
  • Minor trash issues
Note: Distinctions within this grade may include the following:
  • Builder, Natural, and Sapwood grades have longer lengths but more color variations.
  • Character Grade can include longer-length boards but with more knots and color variations.
  • Shorts can have clean faces, but the longest piece may be only 24”.
  • Cabin / Tavern (No Structural Warranty) Cabin / Tavern (No Structural Warranty) This grade tends to have better board lengths and cleaner faces but may include some low-grade wood characteristics and quality imperfections such as machining issues. For the most part, this grade has shorter board lengths, more color variations, and small dings, and is thus expected to have more than a 10% waste factor. Because quality defects are allowed, there is no structural warranty offered on this wood, but a warranty on the finish may be available.
    • A small amount of unfilled knots
    • Small finish defects such as skips, color variations, scratches, and bubbles
    #3 Common / D Grade / Utility (No Structural Warranty) #3 Common / D Grade / Utility (No Structural Warranty) This grade has the shortest board lengths and includes most wood imperfections and machining issues. It is expected to have more than a 10% waste factor. There is no structural warranty offered on this wood, but a warranty on the finish may be available. Most wood imperfections and machining issues
    Shop (No Warranty) Shop (No Warranty) This is the lowest grade in wood flooring – all imperfections are allowed. This grade can be a great value, however, expect more labor, waste, and materials to get a satisfactory final product. All imperfections

    To help illustrate some possible wood defects, the following image highlights some of the acceptable defects in Cabin Grade wood.

    A Few More Things to Consider

    When choosing new flooring for your home or office, it’s important to understand that grade is not determined solely by the appearance of each individual board. Rather, it is determined by the appearance of all of the boards used together to create a floor. Also, as mentioned, a low-grade wood doesn’t necessarily mean that a floor has inferior quality. Grade is a spectrum, where the highest grade represents the cleanest most uniform boards for a particular species. But color is a preference. If you prefer more color variations from board to board and more “character” markings, you may decide to go with a lower grade. What’s most important here is quality. Generally, the lowest-priced woods are those that are of a lower grade and include manufacturing defects that impact overall quality. Narrower board widths and thinner plank thickness will also impact quality, and are often less expensive.

    You also have to consider the wood source. For example, reclaimed woods, which are often sourced from old barns, include a lot of color variations, or patina, from years of wear. While these color variations fall under the low-grade characteristics, in this case, it is actually what makes reclaimed wood uniquely beautiful and often far more expensive – and desirable.

    Find Out More

    To learn more about wood grades or to find the hardwood flooring that best meets your needs, contact your local flooring store.

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    Date: February 1, 2017
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    Very Imformative - just what I needed.Thanks
    Date: January 13, 2017
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    Perfectly stated information. As a journeyman hardwood floor installer (lay sand finish) of 25 years, and as a flooring grade sorter for two years at a flooring mill, I couldnt put it better myself.
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    This gave me a good understanding of the different grades and what to expect
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