Q. I am a small woodworker and buy small quantities of lumber every month. We try to get exactly what we need—species, thickness, etc. This last time, I ordered 502 board feet of lumber. The bundle was 48 inches x 10 feet, with every piece being full length; there were 12 layers. This bundle size has 40 BF per layer, so we got 480 BF, but they charged me for 502 BF which is 5 percent more. My neighbor said that they add to the extra footage to account for shrinkage. Does this make sense?
Answer. Because of a successful lawsuit about the shortage of lumber in a bundle (because the supplier was adding 6 percent to the actual dry footage to account for shrinkage), on July 21, 1977 the National Conference on Weights and Measures adopted the statement, and the National Hardwood Lumber Assn. rules for grading include this as well, that,
"Sales of hardwood lumber measured after kiln drying shall be...on the basis of net board footage with no additional footage for kiln drying shrinkage."
(The NCWM was founded in 1905 by federal law. Their regulations have the effect of law. Their role is the development and implementation of uniform and equitable weights and measures standards.)
To clarify, the NET FOOTAGE for dried lumber is the footage after drying. The GROSS FOOTAGE is the footage of this same lumber prior to drying-and shrinking. However, some folks take the net footage and add the supposed or estimated shrinkage back and then sell dry lumber based on the gross footage-just what the rules and regulation prohibit. It is like getting only 0.92 gallons when you get a gallon of gas, with the missing 0.08 gallons having evaporated during manufacturing and shipping.
It is interesting that this "add back" for lumber was 6 percent years ago, but I have seen it as high as 9 percent today. Is wood today shrinking more than in the past? The 6 percent number is actually close to the amount of shrinkage in BF for flatsawn oak lumber today; quartersawn lumber and many lighter weight species shrink less.
Basically, the regulation and law is that you have to sell a quantity that is the actual quantity at the time of measurement. So, maybe you did indeed get the shrinkage added back. But….
It is indeed possible that you did indeed get 502 BF. Here is why. Hardwood lumber is sold on the basis of board feet without any fractions. For example, with your 10-foot pieces, a piece that is between 6-5/8 to 7-3/4 inches wide is counted as 6 BF. [Recall that BF = width in inches (and fractions) x length in feet (no fractions) divided by 12.] So, if in a 48-inch x 10-foot layer I gave you seven pieces that were each 6-5/8 inches wide for a total width of 48 inches (with a few ¼ inch gaps between some of the pieces), you would have 6 BF x 7 = 42 BF per layer. With 12 layers, the total bundle would be 504 BF of lumber. On the other hand, what if I gave you six wide pieces (7-3/4 inches); then you would have 6 BF x 6 = 36 BF per layer, for a total of only 432 BF in 12 layers.
So, it is possible that you did indeed get 502 BF of lumber if each piece was narrow within its footage range and was measured separately, with the total footage obtained by adding all the individual footages.
For this reason, you should, in the future, specify that the footage is based on the sum of the individual pieces. You might want to avoid the block tally on small loads. On a large load, all the plusses and minuses should average out.
Special note: The NHLA grading rules allow for a few pieces to be scant in width without penalty. This scantness refers to grading and not measuring; the footage is always based on the actual width (inches and fractions) at the time of grading or measuring.
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