Lumber & Framing guide
Plan your lumber & framing project
Why hardwood is sold by the board foot
Hardwood comes in random widths and lengths, so lumber yards price it by volume. One board foot is a piece 12 in long, 12 in wide and 1 in thick, or any piece with the same volume. A 2 in thick board 6 in wide and 1 ft long is also one board foot.
Home centers sell softwood framing lumber like 2 × 4s by the piece instead. Board feet are still useful for comparing prices between the two.
Counting drywall sheets
Work out the wall area as the room perimeter times the wall height, subtract doors and windows, and add the ceiling if you are covering it. Divide by the sheet area and round up, then add about 10% for cuts and breakage.
1/2 in drywall is the usual choice for interior walls. Ceilings, especially with joists 24 in apart, often get 5/8 in board to resist sagging.
Lumber and drywall sizes
| Item | Size | Note |
|---|---|---|
| One board foot | 12 × 12 × 1 in | 144 cubic inches |
| 2 × 4, actual size | 1.5 × 3.5 in | Softwood is named by its rough size |
| 4/4 hardwood | 1 in thick, rough | Hardwood thickness is counted in quarters |
| 4 × 8 drywall sheet | 32 sq ft | Easiest size to carry |
| 4 × 12 drywall sheet | 48 sq ft | Fewer seams on long walls |
Common mistakes
- Using nominal sizes for planed softwood when a yard prices by actual size.
- Mixing up linear feet and board feet on a quote.
- Forgetting the ceiling when ordering drywall.
- Ordering sheets too long to fit up the stairs or through the door.
Frequently asked questions
What is a board foot?
A unit of lumber volume equal to a board 12 in long, 12 in wide and 1 in thick, or 144 cubic inches.
How many board feet are in a 2 × 4 × 8?
Using nominal sizes, 2 × 4 × 8 ÷ 12 is 5.33 board feet. Ask your supplier whether they price by nominal or actual size.
How many sheets of drywall for a 12 × 14 room?
With 8 ft walls, one door, two windows and 10% waste, the walls need 13 sheets of 4 × 8. Add the ceiling if you are covering it too.
What thickness of drywall should I use?
1/2 in is standard for interior walls. 5/8 in is common on ceilings and is required in some fire-rated locations, such as walls between a garage and the house; follow local code.
Sources
- American Hardwood Export Council, Measurement of American hardwood lumber
- Hunker, What Size Does Drywall Come In?