Wood Construction Materials

Hardwood »Comes from deciduous trees such as oak, birch, walnut, maple, and hickory

Softwood Comes from evergreen conifers such as pine, cedar, cypress, fir and redwood

Rough Lumber Rough lumber or nominal sized lumber is the actual size or full dimension A 2” X 4” is actually that size with rough surfaces

Dressed Lumber Dressed or surfaced on all four sides lumber is smaller than rough lumber and is smooth

Dressed Lumber A dressed 2” X 4’ is actually 1 ½” X 3 ½”, and 1” thick boards are actually ¾” thick

Select Lumber Select lumber is free of knots and blemishes, and select grades are A, B, C, and D

Common Lumber Common lumber is general purpose wood and may have knots and blemishes

Common Lumber Grade No. 1 is a general purpose wood that may have sound, smooth knots up to 2” in diameter

Common Lumber Grade No. 2 is used for flooring and framing and has large knots and blemishes

Common Lumber »Grade No. 3 has loose knots or knotholes and is used for shelving and some types of framing

Common Lumber Grade No. 4 and No. 5 are poor quality used for temporary structures

Plywood Plywood is made by gluing odd numbers of veneers (layers) of wood to make 4’ X 8’ or 4’ X 12’ sheets of different thickness

Plywood Hardwood or softwood outside layers

Plywood Exterior plywood has waterproof glue

Plywood Interior plywood may or may not have waterproof glue

Plywood Veneer grade A – best, smooth, paintable, may have some neat repairs

Plywood Veneer grade B – solid, some tight knots, splits and repairs

Plywood Veneer grade C – tight knots up to 1 ½”, knotholes up to 1” splits, discoloration, and defects

Plywood Veneer grade D – knots and knotholes up to 2 ½”, splits

Plywood AC is exterior plywood with A face and C back

Plywood AD is interior plywood with A face and D back

OSB OSB is oriented strand board in the same sizes as plywood

OSB It is made from strands, flakes, or wafers sliced from small diameter logs and bonded with exterior glue under heat and pressure

OSB OSB is engineered so that the wood strands are oriented, not randomly placed like wafer board

Particle Board Manufactured sheets of wood made from ground up scrap wood, sawdust, and glue

Shiplap A board with a rabbet cut on each edge

Tongue and Grooved Boards have a tongue or lip on one edge and a groove on the other edge so that the lip of one side fits into the groove on another board

Board Feet A piece of lumber one inch thick, twelve inches wide, and one foot long

Board Foot Formula BF = T” X W” X L’ 12 Thickness and width are inches; length is feet

Board Feet Example: How many board feet are in a board 1” thick, 12” wide and 10’ long

Board Feet BF = 1 X 12 X 10 = = 10

If there is more than one piece, multiply by number of pieces of lumber of same size Board Feet

Per Thousand Most construction lumber is priced per thousand board feet M = 1000

Per Thousand Example: 10 M BF = 10,000 Board Feet

Wood Construction Materials