Chapter 3 Wood. Qualities of Wood THE MATERIAL WOOD IS: StrongLight Easily handled, worked, & shaped...
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Transcript of Chapter 3 Wood. Qualities of Wood THE MATERIAL WOOD IS: StrongLight Easily handled, worked, & shaped...
Chapter 3Wood
Qualities of WoodQualities of Wood
THE MATERIAL WOOD ISTHE MATERIAL WOOD IS::
StrongStrong
LightLight
Easily handled, worked, & Easily handled, worked, & shapedshaped
Fastened quickly & Fastened quickly & economicallyeconomically
RecyclableRecyclable
BiodegradableBiodegradable
A renewable resourceA renewable resource
Undesirable Characteristics of WoodUndesirable Characteristics of Wood
Not perfectly straightNot perfectly straight
Affected by moistureAffected by moisture
Has growth defectsHas growth defects
But can be protected from:But can be protected from:Splitting & warpingSplitting & warping
BurningBurning
DecayingDecaying
Attack by Insects Attack by Insects
Tree CompositionTree Composition
BarkBark
CambiumCambium
SapwoodSapwood
HeartwoodHeartwood
PithPith
Tree GrowthTree Growth
Springwood Springwood (earlywood)(earlywood)– Faster growthFaster growth– Cells larger and less denseCells larger and less dense
SummerwoodSummerwood (latewood)(latewood)– Slower growthSlower growth– Cells smaller and denserCells smaller and denser
TWO TYPES OF WOODTWO TYPES OF WOOD
Generally, two types of trees provide Generally, two types of trees provide wood:wood:
HARDWOOD is produced by trees that have HARDWOOD is produced by trees that have broad leaves - lose them in winter - reproduce broad leaves - lose them in winter - reproduce them in spring. Species are oak, pecan, them in spring. Species are oak, pecan, walnut, ash, cherry, birch, etc. Slow growth.walnut, ash, cherry, birch, etc. Slow growth.
SOFTWOOD is the type that comes from trees SOFTWOOD is the type that comes from trees that have needles, are evergreen, do not lose that have needles, are evergreen, do not lose them in winter. Species include pine, fir, them in winter. Species include pine, fir, spruce, larch, cedar, etc. Fast growth. Much spruce, larch, cedar, etc. Fast growth. Much more plentiful than hardwoods.more plentiful than hardwoods.
Construction Uses for WoodConstruction Uses for Wood
Structural FramingStructural Framing
Subfloors and Roof SheathingSubfloors and Roof Sheathing
Finish Siding ( generally all softwood)Finish Siding ( generally all softwood)
Finish cabinetry, trim, & paneling Finish cabinetry, trim, & paneling
(generally hardwood(generally hardwood))
How Logs are Cut (softwoods) How Logs are Cut (softwoods)
Plain SlicedPlain Sliced
– Maximum YieldMaximum Yield
– Varying grain patternVarying grain pattern
– Common use - Framing Common use - Framing
lumberlumber
Aesthetic Use (hardwoods)Aesthetic Use (hardwoods)
Quarter SawingQuarter Sawing
– Perpendicular to annual ringsPerpendicular to annual rings
– Less yield, but consistent grain Less yield, but consistent grain pattern for appearancepattern for appearance
– Improved wearing quality, less Improved wearing quality, less distortiondistortion
Lumber Must be Dried for StabilityLumber Must be Dried for Stability
Drying MethodsDrying Methods– Kiln – heated in an oven to drive out moisture (much Kiln – heated in an oven to drive out moisture (much
less time, more costly, most stable)less time, more costly, most stable)
– Air - left to dry in the sun and air (long time, less Air - left to dry in the sun and air (long time, less costly, less control of dimension changes)costly, less control of dimension changes)
Drying EffectsDrying Effects– ShrinkageShrinkage
– Reduced weightReduced weight
– Increase of strength and stiffnessIncrease of strength and stiffness
– More stable dimensionallyMore stable dimensionally
Lumber SurfacingLumber Surfacing
Purpose:Purpose:
– Smooth surfacesSmooth surfaces
– Dimensional precisionDimensional precision
Designations; S2S, S4S, S2EDesignations; S2S, S4S, S2E
– Surface two sides, edges roughSurface two sides, edges rough
– Surface 4 sidesSurface 4 sides
– Surface two edgesSurface two edges
Surfacing is performed after performed after
material is driedmaterial is dried
Rough sawn(not surfaced)
S4S
Lumber DefectsLumber Defects
Growth defectsGrowth defects– Knots Knots – Decay and insect damageDecay and insect damage
Manufacturing DefectsManufacturing Defects– Splits & checksSplits & checks– Crook, bow, Crook, bow, – Cup, twist, tangoCup, twist, tango
Lumber Grade & SpeciesLumber Grade & Species
Graded According ToGraded According To::Strength & Stiffness (Structural Lumber)Strength & Stiffness (Structural Lumber)
Appearance (Finish Lumber)Appearance (Finish Lumber)
Lumber sold byLumber sold by - Species and Grade - Species and GradeBetter Grade Better Grade Higher price Higher price
Scarce or Higher Quality Species Scarce or Higher Quality Species Higher price Higher price
Building Codes & Architectural SpecificationsBuilding Codes & Architectural Specifications
will define permitted material strength characteristics, will define permitted material strength characteristics, which are defined by the lumber grading system. which are defined by the lumber grading system.
Spruce, Fir, or PineStud
Surfaced Dry
No 2 LumberKiln Dried (19% moisture)
Considerations That Affect StrengthConsiderations That Affect Strength
Primary Considerations:Primary Considerations:– SpeciesSpecies– GradeGrade– Direction of Load Vs. GrainDirection of Load Vs. Grain
– Grading of lumber is generally done with Grading of lumber is generally done with softwood material to be used structurallysoftwood material to be used structurally. . Hardwoods are basically a material used for Hardwoods are basically a material used for appearance and durability, and are not graded appearance and durability, and are not graded for structural characteristics.for structural characteristics.
Lumber Size Nomenclature – NOMINAL SIZELumber Size Nomenclature – NOMINAL SIZE
Thickness Thickness – Less than 2 inches – Boards Less than 2 inches – Boards
& Planks& Planks– 2 to 4 in. - Dimension Lumber2 to 4 in. - Dimension Lumber– 5 inches or more - Timbers5 inches or more - Timbers
Nominal Standard SizeNominal Standard Size – Framing Lumber - 2, 4, 6, 8, 10, Framing Lumber - 2, 4, 6, 8, 10,
12 inches (softwood)12 inches (softwood)– Finish lumber (hardwood) no Finish lumber (hardwood) no
standard widths, but finish standard widths, but finish thickness ¾”, 1”, 5/4”, 6/4” thickness ¾”, 1”, 5/4”, 6/4”
Lumber Thickness and Width - ACTUALLumber Thickness and Width - ACTUAL
Structural Lumber is Structural Lumber is rough cutrough cut to nominal to nominal dimensions, 2”x4”, 2”x6”, etc. After drying it is dimensions, 2”x4”, 2”x6”, etc. After drying it is surfaced to specific finish dimensions:surfaced to specific finish dimensions:
Up to 6 inches nominal – Up to 6 inches nominal – actual finish is 1/2 inch actual finish is 1/2 inch lessless. A 2”x4” is actually 1 ½” x 3 ½”.. A 2”x4” is actually 1 ½” x 3 ½”.
More than 6 inches nominal – More than 6 inches nominal – actual finish is 3/4 actual finish is 3/4 inch lessinch less. An 8” x 12” member is actually 7 ¼” x . An 8” x 12” member is actually 7 ¼” x 11 ¼”11 ¼”
Hardwood materials do not follow the same rulesHardwood materials do not follow the same rules..
Standard Framing Lumber LengthsStandard Framing Lumber Lengths Typically, framing lumber is available in Typically, framing lumber is available in increment lengths of two feetincrement lengths of two feet, such as, such as
8’, 10’, 12’, 14’, & 16’ (longer available)8’, 10’, 12’, 14’, & 16’ (longer available)
Exceptions:Exceptions: – 93 inch studs – precut for framing walls with 93 inch studs – precut for framing walls with
standard 8’ ceiling heightsstandard 8’ ceiling heights– Special order lengths include those that might not Special order lengths include those that might not
be economically feasible for a lumber dealer to be economically feasible for a lumber dealer to keep in stock.keep in stock.
Lumber Pricing Unit - Board FeetLumber Pricing Unit - Board Feet
Lumber, including softwood and hardwood is Lumber, including softwood and hardwood is typically measured in quantity in terms of typically measured in quantity in terms of “board “board feet.”feet.”
One board foot = One board foot = 1 inch x 12 inch x 1 foot1 inch x 12 inch x 1 foot
Calculations are based upon Calculations are based upon nominal nominal dimensions;dimensions;number of board feet = number of board feet =
[(thickness” x width”) / 12] x length in feet.[(thickness” x width”) / 12] x length in feet.
Example; 2x8 that is 10 feet longExample; 2x8 that is 10 feet long [ (2x8)/12 ] x 10 = 13.33 board feet.[ (2x8)/12 ] x 10 = 13.33 board feet.
Wood Panel ProductsWood Panel Products
Why Panelize?Why Panelize?– More “controlled” productMore “controlled” product– Efficient use of forest productsEfficient use of forest products– Increase labor productivityIncrease labor productivity
TypesTypes– Plywood panelsPlywood panels– Composite panelsComposite panels– Non veneered panelsNon veneered panels
Veneered Panels - PlywoodVeneered Panels - Plywood
Thin layers of veneer glued togetherThin layers of veneer glued together
Odd number of veneersOdd number of veneers
Alternating direction of veneersAlternating direction of veneers
Face veneers parallelFace veneers parallel
Size: 4’x8’ panelsSize: 4’x8’ panels
Thickness: ¼” to 1” Thickness: ¼” to 1”
Plywood came intoPlywood came into
wide use in the 1950swide use in the 1950s
because of increasebecause of increase
in labor cost.in labor cost.
Non-veneered PanelsNon-veneered Panels
Oriented Strand Board (OSB)Oriented Strand Board (OSB)
WaferboardWaferboard
ParticleboardParticleboard
FiberboardFiberboard
Particleboard
Fiberboard
Oriented Strand Board (OSB)Oriented Strand Board (OSB)
Has long strand-like wood particlesHas long strand-like wood particles
Grain orientation alternates (3-5 layers)Grain orientation alternates (3-5 layers)
Glued and compressedGlued and compressed
Strongest of the Non-veneeredStrongest of the Non-veneered
Uses; Sheathing for floor, roofs, & sidingUses; Sheathing for floor, roofs, & siding
Plywood Compared To OSBPlywood Compared To OSB
According to the “Georgia Pacific According to the “Georgia Pacific Corporation” the largest producer of panel Corporation” the largest producer of panel products:products:1994-19951994-1995– Plywood Production was 19 billion square Plywood Production was 19 billion square
feet and decliningfeet and declining– OSB Production was 10 billion square feet OSB Production was 10 billion square feet
and increasingand increasing1999 - OSB began to outsell plywood.1999 - OSB began to outsell plywood.Reason? Plywood is made of all new Reason? Plywood is made of all new material. OSB is made of scraps. Price of material. OSB is made of scraps. Price of OSB is much less for comparable use.OSB is much less for comparable use.
Waferboard & ParticleboardWaferboard & Particleboard
Waferboard - weak materialWaferboard - weak material– Large wafer-like particles - No orientationLarge wafer-like particles - No orientation– Uses; Low moisture areasUses; Low moisture areas
Particleboard - weak materialParticleboard - weak material– Small wood particles Small wood particles – No orientationNo orientation– Uses; Low moisture areasUses; Low moisture areas
Both products are inferiorBoth products are inferior
where strength is requiredwhere strength is required
and moisture is present.and moisture is present.
Wood Polymer Composite PlanksWood Polymer Composite Planks
““Artificial Wood” not in wide general use because Artificial Wood” not in wide general use because it is new and untested. Probably will be used it is new and untested. Probably will be used extensively in the future because of its stability, extensively in the future because of its stability, durability to weather, and resistance to insects.durability to weather, and resistance to insects.
Advantages:Advantages:– Decay ResistanceDecay Resistance– Easy WorkabilityEasy Workability
Wood FastenersWood Fasteners
NailsNails
Wood & Lag ScrewsWood & Lag Screws
BoltsBolts
Toothed PlatesToothed Plates
Sheet Metal & Metal Framing DevicesSheet Metal & Metal Framing Devices
Machine Driven Staples & NailsMachine Driven Staples & Nails
AdhesivesAdhesives
16d Galvanized
16d Sinker
Deformed Shank
10d Galv. Spiral
Finish Nail
Roofing Nail (far right)
Standard Sizes of Common NailsStandard Sizes of Common Nails
Machine Driven Nails & StaplesMachine Driven Nails & Staples
Nail Guns, Staple gunsNail Guns, Staple guns– Pneumatic (compressed air)Pneumatic (compressed air)– Electric AC powerElectric AC power– Battery operatedBattery operated
Pre-packaged fastenersPre-packaged fasteners– Collated nail packsCollated nail packs– StaplesStaples
Battery Powered Electric Nailer
Collated Nails
Wood ScrewsWood Screws Head typeHead type
Sizing - Sizing - – Gauge & LengthGauge & Length
InstallationInstallation
Holding powerHolding power
UsesUses
Drywall screws Drywall screws
Deck Screws
Types of ‘Heads’
Lag ScrewsLag Screws
Lag ScrewsLag Screws– Large screwsLarge screws– Square or octagonal Square or octagonal
headhead– Installed with wrench Installed with wrench
BoltsBolts
Heavier structural connectionsHeavier structural connections
TypesTypes– MachineMachine– CarriageCarriage
WashersWashers
Toothed PlatesToothed PlatesSheet metal plate punched to form Sheet metal plate punched to form numerous teethnumerous teeth
Used with roof & floor trussesUsed with roof & floor trusses
Machine pressed into membersMachine pressed into members
Sheet Metal Framing AnchorsSheet Metal Framing Anchors
Used mostly in light Used mostly in light Wood Framing asWood Framing as– Joist Hangers Joist Hangers – Framing anchorsFraming anchors– Angle anchorsAngle anchors– Rafter anchorRafter anchor
Limited Use with Limited Use with Heavy Timber or Heavy Timber or Laminated FramingLaminated Framing
AdhesivesAdhesives
Widely used in the manufacture of Widely used in the manufacture of wood productswood products– Wood panelsWood panels– Laminated woodLaminated wood– CabinetryCabinetry
On Site UsesOn Site Uses– Sheathing Sheathing – Floor deckingFloor decking