Chapter 3 Wood

Qualities of Wood Strong & Stiff Light Easily worked / shaped Fastened quickly & economically Recyclable Biodegradable Renewable Resource

Undesirable Characteristics of Wood Not perfectly straight nor precise Size & shape affected by moisture Contains growth defects Can spilt & warp Burns easily Decays Susceptible to Insect Damage

Tree Composition Bark Cambium Sapwood Heartwood Pith PROTECTIVE LAYER OUTSIDE IS DEAD - INSIDE ALIVE Cambium VERY THIN CREATES NEW CELLS Sapwood STORE NUTRIENTS & TRANSMITS SAP THICK - LIVING Heartwood DEAD WOOD PROVIDES STRUCTURAL STABILITY Pith EARLY YEARS GROWTH SMALL - WEAK

Tree Cells Primarily Hollow, Cylindrical Cells Axis running parallel to the tree (grain direction) Tough Cellulose bound by Lignin Impacts the properties of wood Primarily Hollow, Cylindrical Cells - “TRACHEIDS” Axis running parallel to the tree Tough Cellulose bond by Lignin IMAGINE A GROUP OF STRAWS Impact on the properties of wood PARALLEL WITH GRAIN (TUBE) STRONG PERPENDICULAR - WEAK

Types of Trees / Woods Oak Pine Poplar Oak Pine Poplar Softwoods - Coniferous Trees “SOFT” OR “HARD” NOT NECESSARILY LITERALLY SIMPLE MICROSTRUCTURE COARSE UNINTERESTING GRAIN PINE, SPRUCE, FIR, CEDAR MOST OF THE LUMBER USED IN BUILDING WHY??? GROWS FASTER, MORE PLENTIFUL, MORE ECONOMICAL Hardwoods - Broad leafed trees MORE COMPLEX STRUCTURE BEAUTIFUL GRAIN PATTERNS PRIMARILY - FINE CABINETRY & DOORS, TRIMS / ACCENTS OAK, POPULAR, WALNUT, MAPLE Oak Pine Oak Pine Poplar Poplar

Construction Uses for Wood Structural Framing Subfloors and Roof Sheathing Siding - Structural & Exposed Finish cabinetry and Trim Structural Framing GENERALLY PINE, FIR OR SPRUCE Subfloors and Roof decking GENERALLY WOOD PANELS Siding - Structural & Exposed STRUCTURAL - OFTEN WOOD PANELS EXPOSED - NATURALLY DECAY RESISTANT OR TREATED CEDAR, CYPRESS Finish cabinetry and Trim PAINTED OR LAMINATED - PANELS OR SOFTWOODS “EXPOSED”/ FINISHED - HARDWOODS

Lumber Production - Sawing Plain Sawing Maximum Yield Varying grain pattern Common use - Framing lumber 1ST CUT (LOG) AND TRANSPORT TO THE MILL Plain Sawing Maximum Yield Varying grain pattern CAUSES DRYING DISTORTIONS DIFFERENT SURFACE APPEARANCE LESS DURABILITY Most common use - Framing lumber WHY??? NOT SEEN STRUCTURAL QUALITIES ACCEPTABLE ECONOMICAL

Lumber Production - Sawing Quarter Sawing Perpendicular to annual rings Less yield, but consistent grain pattern Improved wearing quality, less distortion

Typical Sawing Method

Lumber Drying Drying Methods Drying Effects Air Kiln Shrinkage Reduced weight Increase of strength and stiffness More dimensional stable WHY DRY WOOD??? WATER IS 30% TO 300% OF DRY WT. Seasoned lumber @ 19% or less HEAVY, WEAKER, LESS STABLE Drying Types Air CUT & STACKED IN OPEN AIR DRIED - CAN TAKE MONTHS Kiln CUT & STACKED KILN DRIED - A MATTER OF DAYS FASTER, HIGHER QUALITY PROCESS Drying Effects Shrinkage LENGTH - NEGLIGIBLE RADIAL - MEASURABLE AMOUNT 12’ BOARD - 30% TO 15% (2% SHRINKAGE - 1/4”) TANGENTIAL - UP TO 50% > RADIAL (STRESSES INDUCED) Reduced weight Increase of strength and stiffness More dimensional stable

Differential Shrinkage (between radial & tangential) during drying can cause distortions

Lumber Surfacing Purpose; Designations; S2S, S4S Smooth Dimensional precision Designations; S2S, S4S Surfacing typically performed before or after drying? Rough sawn (not surfaced) Purpose; Smooth Dimensional precision Designations; S2S, S4S FRAMING - S4S SOME HARDWOODS - S2S Performed primarily after drying WHY??? “SHRINAGE DURING DRYING S4S

Lumber Defects Growth defects Manufacturing Defects Knots & knot holes Decay and/or insect damage Manufacturing Defects Splits & checks Crook, bow, Cup, and/or twist Growth defects Knots & knot holes LIMBS / BRANCHES Decay and/or insect damage MOIST CONDITIONS, BORES Manufacturing Defects Splits & checks Crook, bow, cup, and/or twist WHAT CAUSES THESE DEFECTS??? DIFFERENTIAL SHRINKAGE

Lumber Grade & Species Graded by: Lumber sold by - Species and Grade Strength & Stiffness (Structural Lumber), or Appearance (Finish Lumber) Lumber sold by - Species and Grade Better Grade  Higher price Scarce or Higher Quality Species  Higher price Strength & Stiffness, or STRUCTURAL OR FRAMING LUMBER VARIES - SPECIES AND IMPERFECTIONS Appearance NON-STRUCTURAL OR FINISH LUMBER Effect on price Grade HIGHER GRADE HIGHER ALLOWABLE STRESSES HIGHER PRICE #1 SELECT - DIFFICULT TO FIND #2 &3 MOST COMMON FOR FRAMING BETTER APPEARANCE EXAMPLE; 1 x 12 (priced in 2001) # 3 $1 / BF #2 TWICE (2) THE PRICE OF #3 #1 FIVE (5) TIMES PRICE OF #3

Considerations Affecting Strength Primary Considerations: Species Grade Direction of Load Vs. Grain Other Factors: Length & Time of Maximum Loading Temperature & Moisture Conditions Size & Shape Chemical Treatments Species HARDWOODS TYP. STRONGER (DENSER) Grade LOWER IMPERFECTIONS - INCREASE STRENGTH Direction of Load Vs. Grain Length & Time of Maximum Loading DEFORMATION WHY DESIGN CONSIDERS DEAD AND LIVE LOAD Temperature & Moisture Conditions MOISTURE - DECAY AND STRENGTH REDUCTION Size & Shape SLENDERNESS RATIO

Lumber Thickness and Width - NOMINAL < 2 inches - Boards 2 to 4 in. - Dimension Lumber = to or > 5 inches - Timbers Widths Framing Lumber - 2, 4, 6, 8, 10, 12 inches Finish /lumber - 1 inch (typ.) Thickness - “Nominal” < 2 inches - Boards FRAMING LUMBER - MOST 2 to 4 inches - Dimension Lumber = to or > 5 inches - Timbers Widths - “Nominal” Framing Lumber - 2, 4, 6, 8, 10, 12 inches WHY NOT Typically WIDER??? Finish /lumber - 1 inch (typ.)

Lumber Thickness and Width - ACTUAL Nominal not equal to Actual dimensions Lumber SAWN Close to Nominal Then dried and surfaced Up to 6 inches - actual is 1/2 inch less Greater than 6 inches - actual is 3/4 inch less Nominal not equal to “Actual” dimensions LUMBER “SAWN” Close to Nominal Then dried and surfaced Up to 6 inches - actual is 1/2 inch less Greater than 6 inches - actual is 3/4 inch less WHY THE “BREAK AT 6”??? MORE DISTORTION & SHRINKAGE TO ACCOMMODATE DURING SURFACING

Lumber Pricing Unit - Board Feet One board foot = 1 inch X 12 inch X 1 foot Calculation based upon Nominal dimensions # of board feet = [(thickness” X width”) / 12] X length’ Example; 2x8 that is 10 feet long [(2x8)/12] X 10 = 13.33 board feet (bf)

Lumber Pricing Factors Species Grade (& drying process) Lumber Size FACTORS YOU MUST DECIDE ON WHY DOES SIZE AFFECT COST / BF???

Laminated Wood (Glulam) Lamination Process Why Laminate? Create a size not available naturally Create Shapes Improve Quality Lamination Process SELECT LUMBER, GRADE JOINTS - FINGER OR SCARF ADHESIVES BASED ON EXPECTED MOISTURE Why Laminate? Create a size not available naturally Create Shapes ARCHES, CURVES, ETC. Improved Quality PROCESS CONTROLLED DEFECTS REMOVED / CONSIDERED GRAIN DIRECTION CONTROLLED USES CHURCHES LARGE RESIDENTIAL LODGES, RESTAURANTS

Laminated Wood

Structural Composite Lumber (PSL)

Wood Panel Products Why Panelize? Types More “controlled” product Efficient use of forest products Increase labor productivity Types Plywood panels Composite panels Nonveneered panels Why Panelize? More “controlled” product (strength, shrinkage, etc.) Efficient use of forest products Increase labor productivity Types Plywood Composite panels Veneered panels

Veneered Panels - Plywood Thin layers of veneer glued together Odd number of veneers Alternating direction of veneers Face veneers parallel Size: 4’x8’ panels Thickness: ¼” to 1” Thin layers of veneer glued together VENEERS - ROTARY CUT Odd number of veneers Alternating direction of veneers Face veneers parallel USES SAME AS OSB EXPOSED/PAINTED SURFACES FORMWORK COST MORE THAN OSB

Composite Panels Parallel outside face veneers Core - Reconstituted wood fibers

Veneer Grades Based on the smoothness & integrity of the veneers Classifications; A, B, C (plugged), C, D Price Variances Based on the smoothness & integrity of the veneers Classifications; A, B, C (plugged), C, D B and better sanded smooth Price Variances (2001) 23/32 Exterior A/C = $31 per panel 23/32 Exterior B/C = $20 per panel MOST FORMWORK B/C FINISH AREAS MAY REQUIRE “A” C Plugged C Grade A Grade

Non-veneered Panels Oriented Strand Board (OSB) Waferboard Particleboard Fiberboard Fiberboard Particleboard

Oriented Strand Board (OSB) Long strand like wood particles Alternate grain orientation (3-5 layers) Compressed / glued Strongest of the Non-veneered Uses; Sheathing for floor, roofs, & siding INTRODUCED IN THE EARLY 80’s GETTING WIDESPREAD USE Long strand like wood particles Alternate grain orientation (3-5 layers) Compressed / glued Strongest of the Non-veneered WHY IS IT THE STRONGEST??? ORIENTATION OF STANDS Generally more economical than Plywood Uses; Sheathing for floor, roofs, & siding WHY IS IT GETTING WIDESPREAD USE??? STRUCTURALLY SOUND ECONOMICAL - SUBBSTITUTE FOR PLYWOOD NEW GROWTH TREES

Waferboard & Particleboard Large wafer-like particles - No orientation Uses; Low moisture areas Particleboard Small wood particles No orientation

Structural Ratings Specified by Thickness or Span Rating Span Rating Grade Stamp For veneered & nonveneered Long dimension perpendicular to the support Panel Grade Span Rating IN INCHES PERPENDICULAR TO SUPPORT LARGER # - ROOF SPAN SMALLER # - FLOOR SPAN

Exposure Durability Classifications Exterior - siding or continuous exposure Exposure I; waterproof glue but lower quality veneers Exposure II; protected environments & minimum wetting Thickness Exposure Durability Exterior - siding or continuous exposure Exposure I; Waterproof glue - but veneers are not as high of quality as exterior grade (subfloors, sheathing) - most common rating Exposure II; Minimum wetting

Chemical Treatment Combustibility Decay & Insect FIRE RETARTANT IMPREGNATED UNDER PRESSURE Decay & Insect PRESSURE IMPREGNATED UP TO 30 YEAR LIFE TYPES CREOSOTE PENTACHOROPHENOL - OILY, CAN’T PAINT WATERBORNE SALTS - GREENISH - CAN PAINT Chromated Copper Arsenate (CCA) being phased out HIGH MOISTURE USES – WHY NOT USE DECAY RESISTANT WOODS??? (CEDAR, REDWOOD, CYPRESS) COST & STRENGTH

Wood Polymer Composite Planks Advantages: Decay Resistance Easy Workability

Wood Fasteners Nails Wood & Lag Screws Bolts Toothed Plates Sheet Metal & Metal Framing Devices Machine Driven Staples & Nails Adhesives

Nails Sharpened metal pins Installation: Hammer or mechanical nail gun Common Nails Finish Nails Other types Common flat heads, used mostly for structural connections Finish Nails virtually headless, finish woodwork Common - Used for Framing, Large Shank & Head Box - Smaller Shank, less chance for splitting wood, Used Shingles, Rough Casings Casing, Finish, Brad - Finish Components, Sink Head Deformed Shank - Very Hard to Remove, DW & Flr. Concrete - Masonry & Concrete Cut - Finish Flooring - SQ Head Reduces Cracking Roofing - One of Many, Some Have lead/Rubber Washers

Nails Size - Measured in pennies Coatings Bright/ Plain uncoated steel Corrosion-resistant Resin/Vinyl Size - Measured in “pennies” (Price of 100 nails long ago) Corresponding Lengths Same for Common & Finish Most Common Light Frame Nails - 16d for 2”, 10D AND 8D Coatings Bright/ Plain uncoated steel MOST COMMON USED - NON CORROSIVE OR CONCEALED CONDITION Corrosion-resistant “EXPOSED TO WEATHER RUST OR STAIN LUMBER GALVANIZED, ALUM., SS Resin/Vinyl Decrease Drive & Increase Holding This nail has a smaller shaft – commonly called a ‘sinker’

Anchorage Face, End, or Toe Which Has the Most Holding Power??? Face - Perpendicular to Grain End - Parallel Toe - Angle to Grain Which Has the Most Holding Power??? Which is most common???

Machine Driven Nails & Staples Nail Guns, Staple guns Pneumatic (or electric) Pre-packaged fasteners (collated nails) Improved Productivity Used in many applications Power actuated fasteners APPLICATIONS FRAMING SHEATHING ROOFING Battery Powered Electric Nailer Collated Nails

Wood Screws Head type Sizing - Installation Holding power Uses Types of ‘Heads’ Head type Sizing - Gauge & Length Installation Holding power Uses “Head” type PHILLIPS SLOTTED SQUARE HEAD PAN, FLAT, ROUND, ETC. Sizing - Gauge & Length WIRE GAUGE (SAMPLES #8 & #10) LENGTH IN INCHES (AND FACTIONS) Installation HAND SCREW DRIVER “SCREW GUN”, OR DRILL HOLDING POWER TIGHTER, STRONGER THAN NAILS CAN BE “BACKED” OUT, & REINSERTED Uses CABINETWORK SOME FRAMING APPLICATIONS DECKING - BETTER HOLD - LESS SQUECK Deck Screws

Lag & Drywall Screws Lag Screws Drywall screws Large screws Square or octagonal head Installed w/ wrench Drywall screws Used to attach drywall Lag Screws Large screws Very LARGE Screws, Wrench, ¼ “@ 2-6 in., ½ to 10” FOR HEAVIER STRUCTURAL CONNECTIONS Square or octagonal head Installed w/ wrench Drywall screws Used to attach drywall Drywall Screws (Size, 1 ¼, 1 5/8, 2 “, Screw Gun - Fast, Wood or Metal,

Bolts Heavier structural connections Sizes Types Washers Machine Carriage Washers Heavier structural connections COMMONLY USED W/ TIMBER CONSTRUCTION Sizes 1/4 inch to 1 inch+ LENGTH; ABOUT ANY (PRACTICALLY 10-12”) Types Machine SQUARE OR OCTAGONAL HEAD USED WITH WASHER Carriage ROUND BUTTON HEAD SQUARE SHANK INHIBITS TURNING Washers DISTRIBUTE THE COMPRESSIVE FORCE

Toothed Plates Sheet metal plate w/ numerous teeth Used with roof & floor trusses Pressed into members Very effective fasteners

Sheet Metal Framing Devices Light Wood Framing Joist Hangers Framing anchors Angle anchors Rafter anchor Heavy Timber or Laminated Framing NUMEROUS TYPES AND SHAPES MOST COMMON - JOIST HANGER LIGHT WOOD FRAMING - ATTACHED WITH SCREWS OR NAILS HEAVY TIMBER - ATTACHED WITH BOLTS / LAGS

Adhesives Widely used in the manufacture of wood products On Site Uses Wood panels Laminated wood Cabinetry On Site Uses Sheathing ON SITE LESS USES BECAUSE OF NEED TO CLAMP USES FLOOR SHEATHING BASE (SOLE) PLATES WALL PANELS PANELING (WHERE THERE IS A NEED FOR CONCEALED FASTENERS) INCREASE STIFFNESS, ELIMINATE “SQUEAK”

Wood Manufactured Components Trusses Wood I-Joists Beams Panel Components

Trusses Types of Trusses - Floor & Roof Roof Trusses Floor Trusses

Trusses (cont.) Where and How Built? Order how? Most factory built (pre-engineered) Most 2X4 or 2X6 w/ toothed fasteners Order how? Span Loads Pitch (roof) Overhang

I-Beams Uses Sizes Composition Cost FLOORS & ROOFS Typically, 9-1/2” TO 24 “ DEEP LENGTH UP TO 40 FEET+ Composition & cost TOP & BOTTOM - LUMBER OR Laminated WEB - OSB, PLYWOOD COST - COMPARABLE TO 2x

Why Use Trusses or I-Beams? Less material (less weight) More efficient use of wood Increased Span Increased dimensional stability Installation savings (labor)