Shiplap calculator

80 sq ft, 1x8 with a 1/2 in lap: 18 boards of 8 ft.

Ends and a bad board. A single wall can stay near 0.

Job sheet

Plumb shiplap job sheet

6.75 in reveal.

  • Boards18Each 8 ft board covers 4.5 sq ft.
Plumb shiplap job sheet
6.75 in reveal.

Boards: 18 (Each 8 ft board covers 4.5 sq ft.)

Reveal, then boards

Reveal is the face minus the lap. Coverage of one board is reveal in feet times length. Boards are the wall divided by that coverage, rounded up. Sheet wainscot, which does not lap, is wainscoting. The board-foot price of the stock is board feet.

FAQ

How many shiplap boards for an 8 by 10 wall?

Eighty square feet. A dressed 1x8 is 7.25 inches. A half-inch lap leaves 6.75 inches of reveal. An 8 foot board then covers 4.5 square feet, so 18 boards with no waste.

Why not divide by the full 7.25 inches?

The lap is hidden. Counting the full face under-buys the wall. Type the overlap the mill cuts. A square-edge board with no lap uses 0.

Sources

  1. NIST PS 1 and ordinary dressed lumber: A nominal 1x8 is commonly dressed to 3/4 by 7-1/4 inches. The reveal is that width minus the lap you install.