A board foot is 1 foot long, 1 foot wide, and 1 inch thick, and is used as the unit of measurement.

What is called scantling lumber is 3 or 4 inches wide, and from 2 to 4 inches thick. Joist is usually narrow and deep. When lumber is heavier than joist or scantling it is called timber. Thick boards are called planks. The usual outside covering of wooden houses is siding.

If lumber is less than 1 inch in thickness it is considered as inch in computing the measurement. But a fraction greater than a half-inch is called an inch, and if less than a half it is rejected. A board 4 5-6 inches wide would be considered as 5 inches.

A board 16 feet long, 12 inches wide, and I inch thick would contain (16 X 12 X 1)-:-12, or 16 feet. A board 12 feet long, 14 inches wide, and 3 inches thick, would contain (12 X 14 X 3) -:- 12, or 42 feet, board measure.

To find the number of board feet in any pile of lumber: Multiply the length in feet by breadth in feet and by thickness in inches, and the result by number of boards.