Checks are separations of the wood normally occurring across or through the rings of annual growth, and usually a result of seasoning. The image to the right depicts allowable check sizes by grade based on the following chart. (Remember: Click on the image to enlarge, then click anywhere outside the image to return to the course page)
|C Select||Barely perceptible* on face and back|
|D Select||Barely perceptible* on face. Medium surface check on back|
|Finish**||Small (not over 1/32″ wide and not over 4″ long)|
|Premium**||Medium (not over 1/32″ wide and not over 10″ long)|
|Standard||Surface and Through, ***1/4 length to a maximum of 3′|
|Industrial||Not limited by grade|
* Barely Perceptible is defined as a check that is only visible when held at a favorable angle to the light.
** The reverse face of Finish and Premium shall permit checks equivalent to the face of Standard (1/4 the length to 3′).
*** Tips from the NELMA Inspector: Two quick methods for determining 1/4 the length: 1.) Multiply the length of the board in feet by 3; this will give you 1/4 the length in inches (L’ x 3 = 1/4 L in inches) or 2.) Simply divide the length of the board by 4 to get your answer in feet (L’ / 4 = L in Feet). The first method will bring simplicity to determining lengths on pieces that do not divide evenly. You’ll find that either method will work in any situation, and you can decide which one works best for you.