2. 3
Chapter
Building Materials

3. 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.

4. 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.

5. 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

6. 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

7. Annular Rings Growth layers that form each season Sapwood Heartwood
Contains living cells
May be several inches thick
Heartwood
Formed as sap becomes inactive

8. Kinds of Wood Softwood comes from evergreen trees
Douglas fir
Southern pine
Hardwood comes from broadleaf (deciduous) trees
Beech
Cherry

9. Cutting Methods Softwood Hardwood Flat-grained Edge-grained
Plain-sawed
Quarter-sawed

10. 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

11. 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

12. Seasoning Lumber Seasoning Moisture content of wood can be determined
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

13. 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.

14. Lumber Grades Softwood grades Hardwood grades Boards Dimension Timbers
Factory and shop lumber
Hardwood grades
Firsts and seconds
Selects
Common

15. Lumber Sizes Always used
Nominal dimension is
Always used
Rough unfinished measurement (width and thickness)
Greater than dressed size

16. 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

17. Panel Materials Plywood Composite plywood Nonveneered panels
Thin sheets laminated to various thicknesses
Composite plywood
Veneer faces bonded to wood cores
Nonveneered panels
Particleboard
Fiberboard
Oriented strand board

18. 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

19. Exposure Ratings Two basic categories Durability classifications
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

20. Span Ratings of Plywood
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

21. MDO and HDO Plywood MDO HDO
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

22. Hardwood Plywood Grades
Numbering system for faces and backs of panels
Symbols to indicate grade
Core constructions
Veneer core
Lumber core

23. Oriented Strand Board Made of individual flakes of wood
Parts adhered to each other with resins and glues
Approved for variety of construction projects

24. Composite Board Made of reconstituted wood with veneer on either side
Widely used in modern construction
Sheathing
Subflooring
Siding
Interior wall surfaces

25. 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

26. Hardboard Made of refined wood fibers
Pressed together to form hard, dense material
Standard
Tempered
Tempered hardboard is filled with oils and resins

27. Wood Treatments Pressure-treated lumber Identifying end tag or stamp
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

28. 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

29. 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
Wood panels
Stack on level surface
Keep ventilated
Finish lumber
Open-stack with wood strips for air circulation
Handle with care to prevent soiling and scarring

30. Engineered Lumber
Wood structural units altered through manufacturing processes
Stronger, straighter, and more dimensionally stable than sawn lumber
Components glued together in different configurations

31. Laminated-Veneer Lumber
Produced much like plywood
Used as headers, beams, and columns
Remains stable with predictable performance
Can be stained or left exposed

32. 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

33. I-Joists Have “I” shape
Consist of flanges of structural composite lumber
Light, straight, and strong
Can have knockouts for plumbing and electrical services

34. 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

35. 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

36. 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

37. Thinking Green Cutting custom and fabricated components at lumber mill
Reduces jobsite waste
Eliminates poor storage and other mishaps
Reduces carpenter errors

38. 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

39. 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.

40. 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.

41. Screws Greater holding power than nails
Often used for interior construction
Classified by
Shape of head
Surface finish
Material from which they are made

42. Concrete Used in foundations and slab-on-grade construction
Combination of several materials
Portland cement
Sand
Crushed stone
Water

43. 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

44. 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

45. 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

46. 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

47. 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