Hardwood lumber grades and grading
rules have been established and are governed by the National
Hardwood Lumber Association or NHLA. Flooring
grades have been set and are maintained by the National
Oak Flooring Manufacturers Association or NOFMA.
Sawmills and their customers use the NHLA grading system,
which describes the amount of usable clear material in
a board. Boards with the highest grade—FAS—are
long, wide and free of character marks. Select boards
may contain slight character marks such as pinholes or
small tight knots. The NHLA grading system includes:
| NHLA Grading System |
 |
| •
FAS |
No.
1 Common |
|
| •
Select |
No.
2 Common |
|
| |
No.
3 Common |
|
The NOFMA standards grade oak
and other species of flooring. This system is appearance-based
with grades determined by the occurrence of character
marks. These grades include:
| NOFMA
Grading System |
|
| •
Clear |
No.
1 Common |
|
| •
Select |
No.
2 Common |
|
Clear and Select grades are further
identified by the sawing method. NOFMA also has separate
grading standards for pre-finished flooring–Prime,
Standard and Tavern.  |
|
Hardwood logs become lumber by
one of several sawing methods. Each gives hardwood boards
a distinct grain pattern, along with performance characteristics
you need to consider when specifying.
Plain-Sawn Lumber: cutting tangentially
to a tree’s growth rings produces these boards. That
creates the familiar “flame-shaped” or “cathedral”
grain found in most hardwood flooring and millwork. This
sawing method also produces the most lumber from each
log, making it a cost-effective design choice.
Quarter-Sawn Lumber: This method means
cutting a log radially, or 90-degree angle to the growth
rings. This produces vertical graining, and results in
fewer and narrower boards per log, which increases costs.
Quarter-sawn boards are popular for decorative applications
such as cabinet faces and wainscoting.
Rift-Sawn Lumber: Rift sawing at a 30-degree
or greater angle to the growth rings produces narrow boards
with accentuated vertical or straight grain patterns.
These boards are often favored for fine furniture and
other applications where matching grain is important.
Rift-sawn lumber is available in limited quantities and
species.
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