Board Feet vs Square Feet vs Linear Feet

Posted by Debbie on April 26th, 2002 04:25 PM
In reply to conversion by Kara on April 23rd, 2002 11:36 PM [Go to top of thread]

31 of 75 people found this post helpful

 Moderator Post (s) for this thread:> by doug seibert on 11/11/2004 > by doug seibert on 10/02/2006

Okay gang. Those of us who manufacture milled hardwood flooring use all 3 types of feet to measure wood. LINEAR FEET (1 dimensional) = is only how long a piece of wood measures. SQUARE FEET (2 dimensional) = is how much surface a milled wood product will cover. BOARD FEET (3 dimensional) = measures the VOLUME of wood when sawn before it is kiln-dried (wood shrinks when it is dried) & if it's not rough, then accounts for the milling (like tongue-and-groove flooring or paneling). Most lumber folks converse in board feet. Many users know a piece of rough wood that measures 12" wide x 12" long x 1" thick is 1 board foot. However, if that piece of wood is milled S4S (surface 4 sides or simply, smooth on both faces and edges) then it will actually measure 11-1/4" wide x 12" long x 3/4" thick. If you plan to sheath a boat in boards measure about 6" wide, it is wasteful not to mention expensive to buy 12" wide boards & cut them down to narrower widths. Because wider boards are sawn from older, thicker logs, wider boards cost more per board foot (think volume here) than narrower boards of the same thickness. How to figure this all out? Ask your lumberperson for the STANDARD FINISHED DIMENSIONS of lumber available. Lets say he tells you 4/4x5-1/2 S4S. Figure out how many boards you need at 5-1/2" wide you need to cover each area and the length needed. If the boat is not long, you may be able to buy boards that span the entire length. If not, then figure lengths necessary to attach the joints on the frame. Any lumberperson worth their salt can take your "take off" list & calculate the board feet and give you an estimate for the wood. Specified lengths may cost more depending on how the lumberyard prices lumber (for example: Home Depot sells wood in 2 foot length increments). We have not even discussed what specie of wood (oak, cedar, mahogany, pine, cypress, etc) that is appropriate for boat building/repair or grade (ranking of quality based on direction of board in relation to the log sawn...i.e. plainsawn vs riftsawn vs quartersawn...AND defects allowed...i.e. knots, knot size, heartwood %, sapwood %, wane, cracks, pitchpockets, etc). Grade specs vary from specie to specie. Good luck and write back if you have any questions! Debbie