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8. Wood and Wood Products. Objectives. After studying this chapter, you will be able to: Distinguish between hardwoods and softwoods. Outline the steps in lumber production. Identify various grades and sizes of softwood and hardwood lumber.
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8 Wood and Wood Products
Objectives After studying this chapter, you will be able to: • Distinguish between hardwoods and softwoods. • Outline the steps in lumber production. • Identify various grades and sizes of softwood and hardwood lumber. • Distinguish between plywood, hardboard, medium-density fiberboard, oriented strand board, and waferboard.
Objectives (continued) • Identify various wood panel products. • Distinguish between laminated-veneer lumber, glue-laminated beams, wood I-joists, open-web trusses, and parallel-strand lumber. • Summarize the differences between wood shingles and wood shakes. • Identify other wood products used in construction.
Wood and Wood Products Wood Wood Panel Products Engineered Lumber and Beams Other Wood Products
Wood Classification of Wood Lumber
Wood Classification of Wood • Softwoods: conifers, evergreen trees, includes fir, pine, spruce, cedar, redwood • Hardwoods: deciduous trees, lose leaves, includes ash, cherry, maple, oak, walnut
Wood Lumber • Converting logs into lumber • Seasoning lumber • Lumber classification and grades • Lumber sizes • Lumber uses • Treated and manufactured lumber • Lumber safety
Wood Lumber (continued) • Converting logs into lumber
Wood Lumber (continued) • Seasoning lumber
Wood Lumber (continued) • Lumber classification and grades -Boards: less than 2″ nominal thickness
Wood Lumber (continued) • Lumber classification and grades -Dimension lumber: 2″ 5″ thick -Grade: light-framing
Wood Lumber (continued) • Lumber classification and grades -Dimension lumber: 2″–5″ thick -Grade: stud
Wood Lumber (continued) • Lumber classification and grades -Dimension lumber: 2″ 5″ thick -Grade: structural light-framing: select structural, No. 1 and better, No. 1, No. 2, No. 3
Wood Lumber (continued) • Lumber classification and grades -Dimension lumber: 2″ 5″ thick -Grade: structural joists and planks:select structural, No. 1 and better, No. 1, No. 2, No. 3
Wood Lumber (continued) • Lumber classification and grades -Timbers: greater than 5″ thick - Grades: select structural, No. 1, No. 2
Wood Lumber (continued) • Lumber sizes
Wood Lumber (continued) • Lumber uses -Framing, interior and exterior trim
Wood Lumber (continued) • Treated and manufactured lumber
Wood Lumber (continued) • Lumber safety - Handling long boards - Walking on edges of joists and rafters - Splinters - Treated lumber - Hand and power tools
Green Construction: Sustainable Forestry Timber is a renewable resource, meaning wood and wood products should be sustainable construction materials. However, for many years trees have been harvested more rapidly than they have been replaced. For this reason, other ways must be used to help increase wood and wood product sustainability.
Wood Panel Products Plywood Hardboard Medium-Density Fiberboard (MDF) Oriented Strand Board (OSB) Waferboard Working with Wood Panel Products
Wood Panel Products Plywood • Manufacturing processes: -Rotary cut or sliced veneer -3, 5, or 7 plies assembled with grain at right angles
Wood Panel Products Plywood (continued) • Types -Softwood plywood: strength and stiffness, appearance grades used where panel is visible -Hardwood plywood: lumber-core, veneer-core
Wood Panel Products Plywood (continued) • Sizes -Panel size: 4′ x 8′ -Thicknesses 1/4″, 3/8″ 1/2″, 5/8″, and 3/4″ -Softwood structural panels also available in thicknesses of 15/32″, 19/32″, and 23/32″
Wood Panel Products Plywood (continued) • Grades and uses -Softwood plywood: -Structural grades -Appearance grades
Wood Panel Products Plywood (continued) • Grades and uses -Hardwood plywood, Appearance grades: 1 Premium, 1 Good, 2, 3, 4
Wood Panel Products Hardboard • Made from wood fiber • Grades: standard, tempered, and service • Thicknesses: 1/8″, 3/16″ 1/4″ • Panel size: 4′ x 8′
Wood Panel Products Medium-Density Fiberboard (MDF) • Small wood particles held together with adhesive • Thicknesses: 1/4″ to 17/16″ • Panel Size: 4′ x 8′
Wood Panel Products Oriented Strand Board (OSB) • Long, narrow, strand-like particles held together with adhesive • Assembled in layers with alternating strand direction • Grade stamp much like structural plywood grade stamp • Thicknesses: 1/4″ to 3/4″ • Panel size: 4′ x 8′
Wood Panel Products Waferboard • Particles larger than those used for OSB • Particles randomly oriented • Available in the same sizes and grades as OSB
Wood Panel Products Working with Wood Panel Products • Often easier to cut panels after they are in place • Can be heavy and difficult to handle • Follow correct procedures when using nail gun
Engineered Lumber and Beams Laminated-Veneer Lumber (LVL) Glue-Laminated Beams Wood I-Joists Open-Web Joists Parallel-Strand Lumber
Engineered Lumber and Beams Laminated-Veneer Lumber (LVL) • 1/8″ thick x 8′ long pieces of veneer • Joints staggered • Plies glued together to make long pieces • Used for headers, beams, columns
Engineered Lumber and Beams Glue-Laminated Beams • Made by gluing together several thicknesses of 2″ lumber • Straight glue-laminated used for beams, headers, stair stringers • Curved glue-laminated used to frame arch roofs
Engineered Lumber and Beams Wood I-Joists • Plywood or OSB web • LVL top and bottom chord • Width varies from 9 1/2″ 32″ • Lengths up to 60′
Engineered Lumber and Beams Open-Web Joists • 2 x 4 top and bottom chord • Wood or steel webs • Spans of more than 30′ are possible
Engineered Lumber and Beams Parallel-Strand Lumber • Made from 1/8″ x 1/2″ x 8′ veneer strands • Coated with adhesive • Machine stacked, random end overlap • Cured under pressure • Sawn into finished sizes
Other Wood Products Wood Shingles and Shakes Wood Siding Wood Molding
Other Wood Products Wood Shingles and Shakes • Shingles: sawn to taper from 1/8″ to 1/2″ • Shakes: • Grades: No. 1, No. 2, No. 3, and No. 4
Vertical: plywood and board and batten Other Wood Products Wood Siding • Horizontal: variety of patterns
Floor and wall Other Wood Products Wood Molding • Ceiling
Career Connection: Wood-Related Careers There are a wide variety of occupations related to the production of wood products used in construction. Foresters, heavy equipment operators, sawyers, and inspectors all must meet certain education requirements for their lines of work.