Question 1

What is a board foot?

Accepted Answer

A board foot is a volume measure equal to 144 cubic inches: 1 in × 12 in × 12 in. It is the standard unit for pricing rough lumber.

Question 2

How many board feet in a 2×4×8?

Accepted Answer

A 2 × 4 × 8 lumber piece equals 5.33 board feet ((2 × 4 × 8) ÷ 12).

Question 3

Why is a 2x4 not actually 2 by 4 inches?

Accepted Answer

Because it is named for its rough-sawn size before drying and surfacing. A finished 2×4 measures 1.5 × 3.5 inches under PS 20, the American Softwood Lumber Standard. You are billed by the nominal size, which is the wood as it was cut.

Question 4

What is the difference between nominal and actual lumber size?

Accepted Answer

Nominal is the name — 2×4, 1×6 — and actual is what you measure. Subtract half an inch from nominal dimensions up to 6 inches and three-quarters above: a 2×8 is 1.5 × 7.25, a 2×12 is 1.5 × 11.25.

Question 5

What does kiln-dried mean?

Accepted Answer

The lumber was dried in a controlled chamber to about 19% moisture content or below. It is more dimensionally stable than green or wet-treated stock, which can shrink 5–7% across the grain as it dries and open every joint you cut tight.

Question 6

What lumber grade should I buy?

Accepted Answer

Select Structural and No. 1 for structural work where strength matters, No. 2 for general framing — the usual default — and No. 3 or stud grade for non-structural walls. Grade governs allowable span, which is why span tables always name it.

Question 7

How much does lumber cost?

Accepted Answer

A standard 2×4×8 SPF stud ran roughly $3–5 in 2025, and 2×6 and larger scale up from there. Prices have been unusually volatile since 2020, so a quote more than a few weeks old is not reliable.

Question 8

What is the difference between SPF and SYP?

Accepted Answer

Spruce-Pine-Fir is lighter, more stable, and common in the north. Southern Yellow Pine is denser, stiffer, and holds treatment better, so it dominates pressure-treated stock. SYP spans further for the same size — but only if your span table says so.

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