Wood & Lumber Basics Arch 330 Fall 2008
Wood & Lumber Basics Arch 330 Fall 2008 Look at Master Format2004 Division 06- Wood, Plastics and Composites Maintenance Cleaning, Rehabilitation, Restoration, Preservation Wood Treatment Fire-Retardant Wood Treatment Preservation Wood Treatment Eradication of Insects in Wood Antiseptic Treatment of wood Shop Applied Wood Coatings Look at Master Format2004 Division 06- Wood, Plastics and Composites Rough Carpentry Wood Framing Structural Panels Heavy Timber Treated Wood Foundations Wood Decking Sheathing Shop Fabricated Structural Wood (Manufactured Wood Products) Glued-Laminated Construction Look at Master Format2004 Division 06- Wood, Plastics and Composites Finish Carpentry Millwork Pre-finished Paneling Architectural Woodwork Wood Casework Wood Paneling Wood Stairs and Railings Ornamental Woodwork Wood Trim Wood Frames Structural Plastics and Composites Wood Treatment Fire Retardant Treatment New Issues Decay-Insect Resistance Pressure treated –preservatives (30)yrs. Reduces disadvantages does not eliminate them “The Future” Renewable Resources Old Growth Good Alternate Wood Products Our own material lab- patents on several manufactured products SIPs-Structural Insulated Panels Disadvantages of Wood Construction Can decay, needs care with use, treating or coating Is flammable –needs covering or treating in many uses especially in Engineered Wood Products Quality and availability have decreased Poor insulation characteristics – need to coordinate with insulation Rays Wood & Lumber Basics Trees are divided up into two broad categories: Hardwoods Softwoods Please note: This has nothing to do with the softness or hardness of the wood. Balsa Wood is actually classified as a hardwood! Wood & Lumber Basics Better to divide wood into two broad categories: (I.e. Botany Terms) - Thus Hardwoods are Angiosperms (apple) Seeds on the inside of the fruit and have a flower. With few exceptions they loose there leaves Softwoods are Gymnosperms (Pinecone) Seeds are exposed usually in a cone. Wood & Lumber Basics Main Entry: an·gio·sperm Pronunciation: 'an-jE-&-"sp&rm Function: noun Etymology: ultimately from New Latin angi- + Greek sperma seed -- more at SPERM : any of a class (Angiospermae) or division (Magnoliophyta) of vascular plants (as magnolias, grasses, oaks, roses, and daisies) that have the ovules and seeds enclosed in an ovary, form the embryo and endosperm by double fertilization, and typically have each flower surrounded by a perianth composed of two sets of floral envelopes comprising the calyx and corolla -- called also flowering plant - an·gio·sper·mous /"an-jE-&-'sp&r-m&s/ adjective Main Entry: gym·no·sperm Pronunciation: 'jim-n&-"sp&rm Function: noun Etymology: ultimately from Greek gymnos + sperma seed -- more at SPERM : any of a group of vascular plants that produce naked seeds not enclosed in an ovary, that were formerly considered a class (Gymnospermae) of seed plants, but that are now considered polyphyletic in origin and divided into several extinct divisions and four divisions with surviving members typified by the cycadophytes, conifers, ginkgo, and ephedras -- compare ANGIOSPERM Wood & Lumber Basics Moisture content of wood Living trees moisture as a percentage of wood substance can range from 30 to 200 percent. Water in trees exist as water or water vapor in the cell lumens (cavities) or “bound” within the cell walls. Wood & Lumber Basics Green wood –where the cell walls are completely saturated with water. However Green wood also contains additional water in the lumens Thus the term Green wood would mean freshly cut trees dimensionally stable. As opposed to “green” wood which is term used in grading lumber. Wood & Lumber Basics As we dry wood Water leaves the cell lumens (cavities). However the cell walls are still saturated This is process where water remains in the cell walls but not in the cell lumens or cavities. This is referred to as the….. Fiber Saturation Point Wood & Lumber Basics “Green” condition of lumber is where the lumber is dried to a point below the fiber saturation point. Equilibrium Moisture Content of lumber is where the lumber is dried to where the wood is neither gaining or losing moisture. Once you reach equilibrium moisture content (max. moisture content around 30%), the wood can not take on any more water than the 30%. Wood & Lumber Basics Orthotropic Nature of Wood Longitudinal (shrinks least) Tangential (shrinks most) Radial (Shrinks ½ of tangential) Thus wood is anisotropic material in that it does not shrink equally. Anisotropic causes us the most difficulty in working with wood in combination as to how the wood is milled or cut. Foot note: Least known by today's craftsperson. (½ of tangential) (Shrinks most) (Shrinks least) Anisotropic Milling Very important for finish work Wood Materials I Board Foot Standard measurement Based on Nominal Measurements (Remember nominal are not actual measurements) Calculations (thickness x width) /12” x Length X Number of Pieces Prices are quoted usually by the bf in thousand board feet or M i.e. $456.00 / Mbf =.456 bf Wood is a multiple use building material Structural: Heavy timber framing Light Framing Studs, Beams, Columns Standard Dimensions 2X4 2X6 etc Manufactured Wood Products Glue-Laminated Beams Wood Trussed Rafters Exterior Cladding—plywood, sheathing, siding Engineered Wood Products Heavy Timber Framing Wood plank and beam systems A timber framed custom home Concerns for the future Renewable Resources Old Growth Good Alternate Wood Products Our own material lab- patents on several manufactured products SIPs-Structural Insulated Panels Manufactured Wood Products Wood products glued and manufactured: Better Strength Better Appearance—more dimensional stable More efficient use of wood products Can use smaller logs, wood not normally used for lumber Manufactured Wood Products Glue-Laminated Beams Wood Trussed Rafters Engineered Wood Products Exterior Cladding—plywood, sheathing, siding Glu-Laminated Beams (Glu-Lam) Selected pieces of lumber glued together for stronger beam No seasoning cracking Variety of sizes—long lengths possible Easy availability Variety of grades – visual Wood Trussed Rafters Trusses can be custom fabricated Heavy timber or light dimensional lumber Truss span large area without intermediate support Types of trusses: Fan, scissors, Fink, Prat, etc. Manufactured Wood Products Manufactured lumber Laminated decking Veneer: thin-cut pieces Slicing of veneers: Rotary Plain Quarter Manufactured Wood Panels Exterior ApplicationsSheathing: oriented strand (OSB)(waferboard) sheathing Siding Interior Applications (particleboard) Underlayment Cabinets: Overlay finish Plywood Layers of veneer adhered together by glue, heat, pressure Outside plies are face plies or face and back Various number of plies: 3, 5, 6 Effect stability and quality Structural Plywood: Stamped, waterproof, exterior use or interior protected Veneer Grading: face and back: A,B,C,D-(Ex. CDX) Plywood Types Structural Plywood Sheathing Roof, Wall, Floor- Exterior Glue Exterior Use Siding, soffit Cabinet Work Finish Applications Sheathing Sub-floor Underlayment Wall Sheathing Roofing Box Beams Engineered Wood Products From fast-growing species such as aspen or yellow poplar. Wood Fiber Lightweight Minimum Waste Compatible Engineered Services Product Types TJI Joist ®(Wood I) TJS Truss ®(Open Web) Timber Strand®(LSL) Microllam ®(LVL) Parallam ®(PSL) LSL-Laminated Strand Lumber LVL-Laminated Veneer Lumber PSL-Parallel Strand Lumber Wood Materials I Wood Panel Products Structural Wood Panels Three major categories Plywood Panels Composite Panels – Core wood fibers (cabinet making) Nonveneered Panels • OSB Oriented Strand Board (best of nonveneers) • Waferboard • Particleboard Wood Materials I Plywood veneer grades (& Composite Panels) (Know table and descriptions Table 1 pp. 89) Add “N” grade Better than “A” – specialized veneer N A B C D Best grade of face veneer Worst grade of face veneer N Figure 3.32 & 3.32 (See handout) Figure 3.3
© Copyright 2024