Carpentry

Read Ching, Chapters 4, 5, 6, 7, 10 & 12

  1. What is wood?

    Softwood: conifers

    75% of all lumber production

    Used for framing lumber, sheathing, siding, flooring

    Hardwood: deciduous trees

    Used for finished wood products: interior trim, flooring, doors, and furniture

  2. Wood growth

    Bark

    Cambium layer - outer layer of active cell growth (summer wood)

    Sapwood - carries nutrients to leaves - light color

    Heartwood - no longer active

    Meduliary rays - carries nutrients horizontally across grain

  3. Physical properties of wood

    Moisture content

    1. Free water and embedded water

      Green lumber contains up to 200% moisture

      Ideal moisture content:

      Framing lumber: 15% - 19%

      Interior finish wood: 6% - 12%

    Shrinkage: for every 1% loss of moisture content below 80% wood will shrink 1/30 of total volume

      Methods of reduction of moisture content

      Air drying

      Kiln drying

    Density of wood (at 15% moisture content)

    Pine: 40 pounds per cubic foot

    Fir: 35 pounds per cubic foot

    Structural properties of wood

    Strength of wood will vary with the wood "species" (type of tree) and the quality of the piece of wood, e.g. how many knots it has in it

    Industry organizations publish standard strength values for various species and quality

    Allowable working stresses

    Extreme fiber in bending (Fb) = 1200 to 1500 psi

    Tension parallel with grain (FT) = 900 to 1200 psi

    Horizontal sheer (FV) = 75 to 100 psi

    Compression perpendicular to grain (F'C ||) = 385 to 565 psi

    Compression parallel to grain) (F'C =) = 500 to 1800 psi

    Modulus of Elasticity (E) = 1,200,000 to 1,800,000

  4. Natural defects in wood

    Knots - branches become enclosed within the wood as the tree grows

    Shakes - grain separation between growth rings

    Pitch Pockets - grain separation which contains solid or liquid resins

  5. Damage which may occur to wood

    Rot ("dry" rot)

    can occur when moisture content exceeds 30%

    Caused by bacteria which lives in the moist wood and ingests the wood fibers

    Insects

    Termites

    Carpenter ants

    Carpenter bees

    Prevention and treatment

    Injection of chemical into wood to prevent rot and insect infestation

    Termite shields around foundation

    Termite treatment for extermination

  6. Wood manufacture
    1. Old growth vs. New growth forests
    2. Sawmills
    3. Milling and surfacing
    4. Cross-sectional sizes of framing lumber

      2X2: 1 ½" x 1 ½"

      2X4: 1 ½" x 3 ½"

      2x6: 1 ½" x 5 ½"

      2x8: 1 ½" x 7 ¼"

      2X10: 1 ½" x 9 ¼"

      2X12: 1 ½" x 11 ¼"

    5. Typical lengths of framing lumber readily available from lumber yard:

      8 feet

      10 feet

      12 feet

      14 feet

      16 feet

      18 feet

      20 feet

    6. Sizes of finish wood: 1" nominal thickness is actually 3/4" thick
    7. Veneer production
    8. Oriented strand board (OSB)
  7. Grading of wood members
    1. Grading standards set by industry organizations such as the Southern

    2. Pine Inspection Bureau (SPIB) or the Western Woods Products Association (WWPA)
    3. Grading of wood is done visually
    4. Stress grading
  8. Fabrication of structural wood members
    Roof trusses
    "TJI" Truss-Joist "I" sections (Note: these are not be permitted in Elmhurst)
    Web truss joists
    TJL

     

    Paralam beams
    Microlam LVL beams
    Timberstrand LSL
       

  9. Selection of wood member sizes

  10. Construction in field

  11. Fasteners

    Nails

    History

    Forged

    Wire cut

    Contemporary nail types:

    Common nails

    Common Coated (CC) nails

    Finish nails

    Cut nails

    Galvanized nails

    Roofing nails

    Stainless Steel nails

    Copper nails

    "Pennyweight" (originally meant the cost of nails per 100 nails in England)

    10d (reads as "10 penny") common nails are 2 1/2" long

    16d common nails are 3 1/2" long

    "Cordless" nailer

    Pneumatic nail gun

    Wood screws

  12. House framing

    History

    "Heavy Timber" with nogging

    Balloon framing invented in Chicago

    Western Platform framing

    Structural design

    Purpose of structural design

    To prevent or minimize movement in the building caused by loads which are impinged on it

    Structural action

    Compression

    Tension

    Bending

    Shear

    Torsion

    Compound

    Deflection

    Shortening

    Crippling

    Tearing

    Creep

    Relaxation

    Fatigue

    Types of loads

    Gravity loads

    Dead loads

    Live loads

    Lateral loads

    Wind

    Earthquake

    Torsional loads (twisting)

    Method of structural design

    Calculations based on structural formulae

    Span tables in codes

    Structural elements in buildings

    • Foundations
    • Walls
    • Columns
    • Girders
    • Beams
    • Joists
    • Floor or Roof Deck
    • Trusses
    • Rigid frames
    • Arches
    • Vaults
    • Domes
    • Rafters
    • Purlins
    • Space frames
    • Lateral bracing
    • Moment connections
    • Suspension members

    Typical structural members in houses

    Studs (walls):

    Typical: 2X6 @ 24" o.c.

    Even better for insulation: 2x6 @ 16" o.c. with horizontal 2x3 strapping @ 24" o.c. on interior

    Best for insulation: 2 layers of 2x4 @ 24" o.c. separated by 12" with cavity filled with insulation

    Bracing to stiffen exterior walls against "racking" (sway)

    Plywood sheathing

    OSB sheathing

    Gypsum sheathing with plywood at corners

    Thermas sheathing with plywood at corners

    Let-in bracing (1x4 diagonally nailed to routed out wall studs)

    Metal bracing (Tee shaped metal strip saw-cut (kerfed) into face of wall studs

    Beams

    Lintels above openings

    Exterior openings: use 2 - 2x10s with 2X6 horizontally spiked to vertical members, top and bottom, which makes a 51/2" width - insulation in 2 1/2" wide space between vertical 2x10s.

    Interior openings: use 2 - 2x12s with 1/2" thick plywood filler between, which makes a 3 1/2" width

    Joists:

    Depth and spacing depends on span and species of wood used

    Typical 2x10 @ 16" o.c.

    Rafters:

    Depth and spacing depends on span and species of wood used

    Typical 2x8 @ 16" o.c.

    Deck (floor and roof)

    Typically 3/4" thick tongue-and-groove plywood

    Roof trusses:

    Member size usually 2x4s joined with gang-nail plates

    Trusses are designed by manufacturer based on code-required loads

     

     

  13. Heavy Timber

    Member minimum nominal sizes by code

    Floors - 2" thickness

    Beams - minimum 4" x 4"

    Columns - minimum 4" x 4"

    All members must be exposed to interior spaces and must be visible

    Solid sawn wood

    Glue laminated wood (GluLam)

    Trussed beams

    Wood heavy timber trusses

    Gusset plates

    Split ring connectors

    Bolts

    Types of trusses

    Bowstring  
    King post  
    Queen post  
    Warren truss
    Pratt Truss
    Howe Truss
    Scissors truss

     

     

     

     

     

     

     

    GluLam Rigid frames

    GluLam Arches

  14. Plywood

    Definition of plywood:

    Flat panels of wood made up of wood veneer sheets 1/10" to 1/16" thick, placed at right angles to one another and glued together

    Types of plywood

    Construction (softwood)

    Decorative (paneling, hardwoods)

    Grades

    Engineered Grades

    C-D Interior Structural I

    C-D Interior Structural II

    CC Exterior

    Stamped with 2 numbers on each piece:

    1st number: Maximum support spacing for use as roof sheathing

    2nd number: Maximum support spacing for use as subflooring

    Interior appearance grades

    N: select all-heartwood or all-sapwood for natural finish

    A: smooth, for paint finish

    B: solid surface veneer

    C: tight knots, some splits

    D: knotholes not filled

    Overlays

    Resin impregnates fiber sheets

    High density (for use as concrete formwork)

    Medium density (for use in doors)

    Decorative Plywood

    Softwood core and hardwood veneers from over 50 species (Luan, walnut, oak, birch, and gum are most popular)

    Cut

    Rotary

    Flat (plain) sliced

    Quarter sliced

    Half round sliced

    Rift cut

    Related panels:

    Particleboard

    Hardboard (Masonite)

    Oriented Strand Board (OSB)

    Fiber board (Homosote)

    Applications of plywood

    Flooring structural decks

    Underlayment

    Sheathing

    Walls

    Roofs

    Siding

    Stamped or sawn patterns

    Pressed figures

    Siding

    Clapboard

    Board and Batten

    Tongue and groove boards

    T-111 plywood

  15. Wood for interior finishes

    Species

    Oak

    Maple

    Cherry

    Walnut

    Butternut

    Teak

    Honduras mahogany

    Birch

    Poplar

    Ash

    Cut

    Plain sawn

    Quarter sawn

    Rift sawn

    Applications

    Doors

    Windows

    Door and window casings

    Wainscot

    Baseboards

    Base shoes

    Chair rails

    Plate rails

    Picture rails

    Crown moldings

    Stairs

    Paneling

    Millwork

    Ceilings

    Floors