Chapter 3 Building Materials Objectives Describe the hardwood

Chapter 3 Building Materials

Objectives • Describe the hardwood and softwood classifications. • Define moisture content (M. C. and E. M. C. ). • Identify common defects in lumber. • Define lumber grading terms. • Calculate lumber sizes according to established industry standards. • Explain plywood, OSB, hardboard, and particleboard grades and uses. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Objectives (Cont. ) • List precautions to observe while working with treated lumber. • Identify types of engineered lumber and list their uses and advantages. • Discuss the uses of light gage steel framing. • Identify a variety of metal framing connectors and indicate where each is used. • Identify nail types and sizing units. Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Lumber • Natural or engineered sawmill products – Boards used for flooring, sheathing, and trim – Dimension lumber – Timbers used for posts, beams, and stringers – Specialty items Andy Dean Photography/Shutterstock. com Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Wood Structure and Growth • Wood contains narrow cells called fibers or tracheids • Lignin holds cells together • Cambium is layer of cells just inside bark N. C. Brown Center for Ultrastructure Studies, State University of New York, College of Environmental Science and Forestry, Syracuse, NY Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Annular Rings • Growth layers that form each season • Sapwood – Contains living cells – May be several inches thick • Heartwood – Formed as sap becomes inactive Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Kinds of Wood • Softwood comes from evergreen trees – Douglas fir – Southern pine • Hardwood comes from broadleaf (deciduous) trees – Beech – Cherry Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Cutting Methods • Softwood – Flat-grained – Edge-grained • Hardwood – Plain-sawed – Quarter-sawed Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Moisture Content and Shrinkage • Moisture content is percent of oven dry weight – Free water – Bound water – Fiber saturation point • Wood shrinks most along direction of annual rings Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Equilibrium Moisture Content • Point at which moisture in wood is balanced with that in air • Moisture content (MC) is always changing • MC varies in different geographical areas Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Seasoning Lumber • Seasoning – Reducing MC of lumber to required level – Air drying – Kiln drying • Moisture content of wood can be determined – Oven drying sample – Using electronic moisture meter Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Lumber Defects • Irregularities occurring in or on wood • Reduce wood’s strength, durability, or usefulness • May detract from or improve the wood’s appearance Western Wood Products Assn. Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Lumber Grades • Softwood grades – – Boards Dimension Timbers Factory and shop lumber • Hardwood grades – Firsts and seconds – Selects – Common Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Lumber Sizes • Nominal dimension is – Always used – Rough unfinished measurement (width and thickness) – Greater than dressed size Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Calculating Board Footage • Board foot is unit of measure for lumber • Formula for board feet – T is thickness of board (in. ) – W is width (in. ) – L is length (ft. ) bd. ft. = No. pcs. × T × W × L 12 Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Panel Materials • Plywood – Thin sheets laminated to various thicknesses • Composite plywood – Veneer faces bonded to wood cores • Nonveneered panels – Particleboard – Fiberboard – Oriented strand board Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Grade-Trademark Stamp • Quality grades for plywood – Lettering system indicates veneer quality – Name indicates intended use or “performance rating” – APA trademark and grade stamp APA-The Engineered Wood Association Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Exposure Ratings • Two basic categories – Exterior type, 100% waterproof glueline – Interior type, moisture-resistant glueline • Durability classifications – Exterior: Fully waterproof adhesives – Exposure 1: Waterproof bond – Exposure 2: Interior type with intermediate glue Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Span Ratings of Plywood • Span rating – Maximum center-to-center distance between supports • Example – Sheathing may have span ratings of 24/0, 24/16, 40/20, or 48/24 APA-The Engineered Wood Association Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

MDO and HDO Plywood • MDO – Exterior-type panel with 100% waterproof adhesive – Readily accepts paint • HDO – Made with thermosetting resin-impregnated fiber surface – More rugged than MDO APA-The Engineered Wood Association Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Hardwood Plywood Grades • Numbering system for faces and backs of panels • Symbols to indicate grade • Core constructions – Veneer core – Lumber core Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Oriented Strand Board • Made of individual flakes of wood • Parts adhered to each other with resins and glues • Approved for variety of construction projects Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Composite Board • Made of reconstituted wood with veneer on either side • Widely used in modern construction – – Sheathing Subflooring Siding Interior wall surfaces Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Particleboard • Used in cabinetwork – Drawer bottoms – Concealed panels in cases and chests • Made of wood flakes, chips, and shavings • Bonded together with resins or adhesives • Used as base for veneers and laminates Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Hardboard • Made of refined wood fibers • Pressed together to form hard, dense material – Standard – Tempered • Tempered hardboard is filled with oils and resins Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Wood Treatments • Pressure-treated lumber – Resists termites and fungal decay – Used for outside jobs • Identifying end tag or stamp • Major types of liquid preservatives – Waterborne – Oilborne – Creosote Southern Pine Council Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Safety Note • Environmental Protection Agency (EPA) warning – Treated wood should never be used where waterborne arsenical preservatives in treatment may become component of food, animal feed, or drinking water Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Handling and Storing Lumber • Piles of framing lumber and sheathing – Place on level skids raised above ground – Cover with canvas, waterproof paper, or polyethylene film • Finish lumber – Open-stack with wood strips for air circulation – Handle with care to prevent soiling and scarring • Wood panels – Stack on level surface – Keep ventilated Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Engineered Lumber • Wood structural units altered through manufacturing processes • Stronger, straighter, and more dimensionally stable than sawn lumber • Components glued together in different configurations Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Laminated-Veneer Lumber • Produced much like plywood • Used as headers, beams, and columns • Remains stable with predictable performance • Can be stained or left exposed Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Glue-Laminated Beams • Also called glulams • Made by gluing and applying pressure to layers • Come in two types – Balanced – Unbalanced • Made in custom and stock sizes Rik Vandermeulen, Unalam Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

I-Joists • Have “I” shape • Consist of flanges of structural composite lumber • Light, straight, and strong • Can have knockouts for plumbing and electrical services Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Open-Web Trusses • Sometimes used in place of floor joists • Fabricated in factories from solid 2 × 4 lumber • Allow installation of pipes and wiring via open webs Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Parallel-Strand Lumber • Made of 1″ by 8′ strands of veneer coated with adhesive • Veneer strips form billets of various lengths • Lumber yards cut billets to specified lengths • Can be pressure-treated for outdoor use Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Laminated-Strand Lumber • Made of strands of wood bonded with polyurethane adhesive • Available in two thicknesses: 1 1/4″ and 3 1/2″ • Examples of use – Door and window headers – Rim joists in floors – Core stock for flush doors with veneer overlays Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Thinking Green • Cutting custom and fabricated components at lumber mill – Reduces jobsite waste – Eliminates poor storage and other mishaps – Reduces carpenter errors Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Light Gage Steel Framing • Found in light commercial buildings and residential construction • Attached to base and ceiling channels with screws • Used for partitions and nonloadbearing walls Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Metal Framing Connectors • Stamped brackets or strapping designed to make connections – Wood-to-wood – Wood-to-masonry – Wood-to-concrete • Tension bridging • Metal corner braces ©Simpson Strong-Tie Company, Inc. Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Nails • Available in range of types and sizes – – – Common Box Casing Finish Brad • Come in size units called penny (abbreviated d) ©Simpson Strong-Tie Company, Inc. Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Screws • Greater holding power than nails • Often used for interior construction • Classified by – Shape of head – Surface finish – Material from which they are made Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Concrete • Used in foundations and slab-on-grade construction • Combination of several materials – – Portland cement Sand Crushed stone Water Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Adhesive Bonding Agents • Carpenters use several bonding materials – Glues come from natural materials – Adhesives are developed from synthetic materials – Cements and mastics are rubber-based • Some have longer curing times than others • Joints may need to be clamped securely during curing time Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Safety Note • Never use flammable contact cement in building with open flames – Space heater – Kitchen range pilot light – Furnace • Fumes are very flammable and may result in explosion Copyright Goodheart-Willcox Co. , Inc. May not be posted to a publicly accessible website.

Mastics • Include waterproofing materials and adhesives – Liquids – Pastes • Vary in characteristics and application methods • Usually packaged in metal or plastic containers or in gun cartridges Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Open Time • Amount of time between spreading material and when parts must be clamped • Also called setting time • Varies with temperature and humidity • Adhesives easily spread at open times as indicated by manufacturer Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.

Staples • Used as fasteners for various applications • Applied with – Pneumatic staplers – Electric staplers – Hand staplers • Available in various lengths, widths, and thicknesses (gages) • Come in different point types Copyright Goodheart-Willcox Co. , Inc. May notnot be posted to atopublicly accessible website. Copyright Goodheart-Willcox be posted a publicly accessible website.