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Ag. Productions I. Agricultural Mechanics 26.00-Apply procedures used to purchase and calculate construction materials. Grades of Lumber. Hardwood or Softwood? Hardwood comes from deciduous trees Oak, birch, walnut, maple, and hickory Softwood comes from evergreen conifers
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Ag. Productions I Agricultural Mechanics 26.00-Apply procedures used to purchase and calculate construction materials
Grades of Lumber • Hardwood or Softwood? • Hardwood comes from deciduous trees • Oak, birch, walnut, maple, and hickory • Softwood comes from evergreen conifers • Pine, cedar, cypress, fir, and redwood
Roughed or Dressed? • Rough or nominal sized lumber us the actual size of full dimension. • A 2” X 4” is actually that size with rough surfaces • Dressed or surfaced on all four sides lumber is small than rough lumber and is smooth. • A dressed 2” X 4” is actually 1 ½” X 3 ½” • 1” thick boards are actually ¾”
Select or Common? • Select lumber is free of knots and blemishes • Grades A, B, C, or D • Common lumber us general purpose wood that may have knots or blemishes • Grade No. 1- may have sound smooth knots up to 2” in diameter • Grade No. 2- used for flooring and framing and has large knots or blemishes • Grade No. 3- has loose knots and is used for shelving • Grade No. 4 and No. 5- poor quality used for temporary structures
Plywood is made by gluing odd numbers of veneers (layers) of wood to make 4’X8’ or 4’X12’ sheets of different thickness
Plywood • Hardwood or softwood outside layers • Exterior has waterproof glue • Interior may or may not have waterproof glue • Veneer grades • A-best, smooth, and paintable • B- solid, some tight knots or splits • C- tight knots up to 1 1/2’” and up to 1” splits • D-knots and knotholes and up to 2 ½” splits
AC is exterior plywood with A face and C back • AD is interior plywood with A face and D back
OSB is Oriented Strand Board • It is made from strands, flakes, or wafers sliced from small diameter logs and boned with exterior glue under heat and pressure • OSB is engineered so that the wood strands are oriented, not randomly placed like wafer board
Particle board • Manufactured sheets or wood made from group up scrap wood, sawdust, and glue
Shiplap • Board with a rabbet cut on each edge
Tongue and groove boards • Have a tongue or lip on one edge and a groove on the other edge so that the lip of one side sits into the groove on another board
Board Feet • Board foot is a piece of lumber • One inch thick • 12 inches wide • One foot long
Formula • BF= T” X W” X L’ 12 • Note: Thickness and width are in inches. Length is in feet.
If there is more than one piece, multiply by number of pieces of lumber of the same size
Square Feet • Many building materials are sold by the square foot or in units that combine square footage such as a square or sheet • Square foot is 12” X12” or 144 square inches