Key takeaways
- Square feet is width times height for walls, ceilings and floors. Board feet is thickness in inches times width in inches times length in feet, divided by 12.
- Add 10 percent waste for straight, even boards and 15 to 20 percent for random widths, character grade or diagonal layouts.
- Subtract large openings, but not small outlets and switches.
- Order from one lot, because color shifts between batches of old wood.
Square feet for walls, ceilings and floors
Measure the width and height of each surface in feet and multiply. Add the surfaces together, then subtract large windows and doors. Do not bother subtracting outlets, switches or small vents, because the cuts around them create waste anyway.
A 12 by 9 foot accent wall is 108 square feet. With 15 percent waste for a random-width layout, order about 124 square feet.
Board feet for thick stock
A board foot is a piece of wood 1 inch thick, 12 inches wide and 1 foot long. To find it, multiply thickness in inches by width in inches by length in feet, then divide by 12. A 2 by 10 inch board that is 8 feet long holds 2 x 10 x 8 / 12 = about 13.3 board feet.
Use board feet for beams, slabs, mantels and table stock. Use square feet for anything that covers a surface.
Waste, widths and lots
Waste depends on the layout and the wood. Straight runs of even boards need about 10 percent. Random widths, character grade, herringbone and diagonal layouts need 15 to 20 percent, because you cut around knots, checks and damage.
Order everything for one project at once. Old wood changes color from lot to lot, and a second order a month later may not match the first.
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Quick answers
Do I count the actual or nominal board size?
For finished stock, use the actual size you will receive. Ask the supplier which size the price is based on.
How do I figure out how many boards I need?
Divide your square feet with waste by the coverage of one board, which is its width in feet times its length in feet.
Ready to talk it through? Get a free quote or call 615-357-7797.