WOOD CONSTRUCTION Uses and Characteristics Types of Wood Manufacturing Process (milling & seasoning) Part 1 Professor Bran...
Sustainability in Wood Construction <ul><li>Only major renewable structural material </li></ul><ul><li>Forestry Practices ...
CHARACTERISTICS OF WOOD <ul><li>Qualities of Wood </li></ul><ul><ul><li>High strength relative to it’s weight </li></ul></...
CHARACTERISTICS  OF WOOD <ul><li>Undesirable Qualities of Wood </li></ul><ul><ul><li>Not perfectly straight nor precise  <...
USES OF WOOD <ul><li>Structural  </li></ul><ul><ul><li>Light-wood framing </li></ul></ul><ul><ul><li>Heavy-timber framing ...
TYPES OF WOOD <ul><li>Hardwoods </li></ul><ul><ul><li>“ Leafy” (oak, cherry, etc.) </li></ul></ul><ul><ul><ul><li>Deciduou...
TYPES OF WOOD <ul><li>Softwoods </li></ul><ul><ul><li>“ Needles” (evergreens) </li></ul></ul><ul><ul><ul><li>Non-deciduous...
<ul><li>SOFTWOODS </li></ul><ul><ul><li>75% lumber in country </li></ul></ul><ul><ul><li>Fir, white pine, hemlock, cedar, ...
PARTS OF A TREE  (wood growth) <ul><li>Pith:  absolute center of tree </li></ul><ul><li>Heartwood:  inactive cells that pr...
PARTS OF A TREE   (wood growth) <ul><li>Rays:  run perpendicular to fibers and carry food across the grain; these produce ...
Tree Composition <ul><li>Bark </li></ul><ul><li>Cambium </li></ul><ul><li>Sapwood </li></ul><ul><li>Heartwood </li></ul><u...
Tree Cells <ul><li>Primarily Hollow, Cylindrical Cells </li></ul><ul><ul><li>Axis running parallel to the tree (grain dire...
Professor Brandi R. Shepard© ACH 121-Materials and Methods 1
Tree Growth <ul><li>Springwood (earlywood) </li></ul><ul><ul><li>Faster growth </li></ul></ul><ul><ul><li>Cells larger and...
GROWTH CHARACTERISTICS <ul><li>Knots </li></ul><ul><ul><li>Formed by branches </li></ul></ul><ul><li>Shakes </li></ul><ul>...
MANUFACTURING PROCESS <ul><li>Sawing, edging and trimming logs into square or rectangular pieces of wood </li></ul><ul><li...
MANUFACTURING PROCESS <ul><li>Trees are cut and transported to mill </li></ul><ul><li>Logs are cut into shorter lengths </...
MANUFACTURING PROCESS <ul><li>Rough cants, timbers, planks & boards are sent through an  edger </li></ul><ul><ul><li>Remov...
MANUFACTURING PROCESS <ul><li>Plainsawing: </li></ul><ul><ul><li>Better yield from the log </li></ul></ul><ul><ul><li>Chea...
Typical Sawing Method Typical Sawing of a Large Log
Typical Sawing Method
MANUFACTURING PROCESS <ul><li>After sawmilling, lumber is seasoned. </li></ul><ul><ul><li>Kiln-dried or air-dried </li></u...
MANUFACTURING PROCESS <ul><li>Moisture Content: </li></ul><ul><li>Amount (percentage) of moisture (water) in the lumber </...
SEASONING- Shrinkage <ul><li>Heartwood: oldest and strongest part of the tree </li></ul><ul><li>More shrinkage  PERPENDICU...
SEASONING- Shrinkage <ul><li>Lumber Defects </li></ul><ul><ul><li>Crook </li></ul></ul><ul><ul><li>Cup </li></ul></ul><ul>...
SEASONING- Moisture Content <ul><li>Moisture content varies </li></ul><ul><ul><li>26-32% when cut </li></ul></ul><ul><ul><...
MANUFACTURING PROCESS <ul><li>Lumber is then sent to planing mill </li></ul><ul><ul><li>Sizing and surfacing </li></ul></u...
Additional Resources The Encyclopedia of Wood by: Aidan Walker <ul><li>Check out class WebCT site: </li></ul><ul><ul><li>A...
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ACH 121 Lecture 07 (Wood) Part 1

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  • Bark PROTECTIVE LAYER OUTSIDE IS DEAD - INSIDE ALIVE Cambium VERY THIN CREATES NEW CELLS Sapwood STORE NUTRIENTS &amp; TRANSMITS SAP THICK - LIVING Heartwood DEAD WOOD PROVIDES STRUCTURAL STABILITY Pith EARLY YEARS GROWTH SMALL - WEAK
  • 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
  • Springwood (earlywood) Faster growth Cells larger and less dense Summerwood (latewood) Slower growth Cells smaller and denser APPEARS DARKER HENCE - THE RINGS
  • ACH 121 Lecture 07 (Wood) Part 1

    1. 1. WOOD CONSTRUCTION Uses and Characteristics Types of Wood Manufacturing Process (milling & seasoning) Part 1 Professor Brandi R. Shepard© ACH 121-Materials and Methods 1
    2. 2. Sustainability in Wood Construction <ul><li>Only major renewable structural material </li></ul><ul><li>Forestry Practices </li></ul><ul><ul><li>Sustainable forestry </li></ul></ul><ul><ul><li>Clearcutting & replanting </li></ul></ul><ul><li>Mill Practices – Lumber Recovery Factor (LRF) </li></ul><ul><li>Transportation </li></ul><ul><li>Embodies Energy Content </li></ul><ul><li>Construction Process </li></ul>
    3. 3. CHARACTERISTICS OF WOOD <ul><li>Qualities of Wood </li></ul><ul><ul><li>High strength relative to it’s weight </li></ul></ul><ul><ul><ul><li>In compression & tension </li></ul></ul></ul><ul><ul><ul><li>Bending & resistance to impact </li></ul></ul></ul><ul><ul><li>Easy to work with </li></ul></ul><ul><ul><ul><li>Simple tools to create desired shapes </li></ul></ul></ul><ul><ul><li>Highly durable </li></ul></ul><ul><ul><li>Excellent insulating qualities </li></ul></ul><ul><ul><li>Fastened quickly & economically </li></ul></ul><ul><ul><li>Recyclable </li></ul></ul><ul><ul><li>Biodegradable </li></ul></ul><ul><ul><li>Renewable Resource </li></ul></ul>
    4. 4. CHARACTERISTICS OF WOOD <ul><li>Undesirable Qualities of Wood </li></ul><ul><ul><li>Not perfectly straight nor precise </li></ul></ul><ul><ul><li>Size & shape affected by moisture </li></ul></ul><ul><ul><li>Contains growth defects </li></ul></ul><ul><ul><li>Can spilt & warp </li></ul></ul><ul><ul><li>Burns easily </li></ul></ul><ul><ul><li>Decays </li></ul></ul><ul><ul><li>Susceptible to Insect Damage </li></ul></ul>
    5. 5. USES OF WOOD <ul><li>Structural </li></ul><ul><ul><li>Light-wood framing </li></ul></ul><ul><ul><li>Heavy-timber framing </li></ul></ul><ul><li>Non-Structural </li></ul><ul><ul><li>Interior partitions (studs), blocking </li></ul></ul><ul><ul><li>Finished Carpentry </li></ul></ul><ul><ul><ul><li>Flooring, panels, moldings, shelving </li></ul></ul></ul><ul><ul><li>Architectural Woodwork </li></ul></ul><ul><ul><ul><li>Cabinetry/Furniture, drawers, cornices, mantels </li></ul></ul></ul>
    6. 6. TYPES OF WOOD <ul><li>Hardwoods </li></ul><ul><ul><li>“ Leafy” (oak, cherry, etc.) </li></ul></ul><ul><ul><ul><li>Deciduous (loses leaves) </li></ul></ul></ul><ul><ul><li>Overall generally stronger </li></ul></ul><ul><ul><li>Grow slower </li></ul></ul><ul><ul><li>$$$$ cost more </li></ul></ul><ul><ul><li>Used for trim lumber </li></ul></ul><ul><ul><ul><li>Flooring, cabinetry/furniture, interior paneling </li></ul></ul></ul>
    7. 7. TYPES OF WOOD <ul><li>Softwoods </li></ul><ul><ul><li>“ Needles” (evergreens) </li></ul></ul><ul><ul><ul><li>Non-deciduous (does not lose leaves) </li></ul></ul></ul><ul><ul><ul><li>Called “conifer”, bears cones </li></ul></ul></ul><ul><ul><li>Overall generally weaker </li></ul></ul><ul><ul><li>Grow quicker & Cost less </li></ul></ul><ul><ul><li>Used for framing lumber </li></ul></ul><ul><ul><ul><li>Sheathing (roofing & exterior panels) </li></ul></ul></ul><ul><ul><li>Types of trees </li></ul></ul><ul><ul><ul><li>SPF (spruce-pine-fir) </li></ul></ul></ul><ul><ul><ul><li>Hem-fir (hemlock & fir) </li></ul></ul></ul><ul><ul><ul><li>Yellow pine </li></ul></ul></ul>
    8. 8. <ul><li>SOFTWOODS </li></ul><ul><ul><li>75% lumber in country </li></ul></ul><ul><ul><li>Fir, white pine, hemlock, cedar, aspen, spruce, cypress </li></ul></ul><ul><li>HARDWOODS </li></ul><ul><ul><li>Grows mostly in central region </li></ul></ul><ul><ul><li>Maple, birch, beech, ash, cherry, poplar, walnut, oak, hickory </li></ul></ul>
    9. 9. PARTS OF A TREE (wood growth) <ul><li>Pith: absolute center of tree </li></ul><ul><li>Heartwood: inactive cells that provide structural support for tree </li></ul><ul><li>Cambium layer: 3-5 cell thick zone of active cell growth just beneath the inner bark </li></ul><ul><li>Sapwood: carries sap (food) from roots to leaves </li></ul>Fig. 6.1-3
    10. 10. PARTS OF A TREE (wood growth) <ul><li>Rays: run perpendicular to fibers and carry food across the grain; these produce the decorative grain effects </li></ul><ul><li>Inner bark: carries food (oxygen) from leaves to tree & roots) </li></ul><ul><li>Outer bark: dry, dead tissue; protects tree </li></ul><ul><li>Growth ring: made up by summer wood & spring wood; shows age of tree in years </li></ul>
    11. 11. Tree Composition <ul><li>Bark </li></ul><ul><li>Cambium </li></ul><ul><li>Sapwood </li></ul><ul><li>Heartwood </li></ul><ul><li>Pith </li></ul>
    12. 12. Tree Cells <ul><li>Primarily Hollow, Cylindrical Cells </li></ul><ul><ul><li>Axis running parallel to the tree (grain direction) </li></ul></ul><ul><ul><li>Tough Cellulose bound by Lignin </li></ul></ul><ul><li>Impacts the properties of wood </li></ul>
    13. 13. Professor Brandi R. Shepard© ACH 121-Materials and Methods 1
    14. 14. Tree Growth <ul><li>Springwood (earlywood) </li></ul><ul><ul><li>Faster growth </li></ul></ul><ul><ul><li>Cells larger and less dense </li></ul></ul><ul><li>Summerwood (latewood) </li></ul><ul><ul><li>Slower growth </li></ul></ul><ul><ul><li>Cells smaller and denser </li></ul></ul>
    15. 15. GROWTH CHARACTERISTICS <ul><li>Knots </li></ul><ul><ul><li>Formed by branches </li></ul></ul><ul><li>Shakes </li></ul><ul><ul><li>Grain separation between growth layers </li></ul></ul><ul><li>Pitch Pockets </li></ul><ul><ul><li>Grain separation that contains solid or liquid resin </li></ul></ul>
    16. 16. MANUFACTURING PROCESS <ul><li>Sawing, edging and trimming logs into square or rectangular pieces of wood </li></ul><ul><li>Yard lumber </li></ul><ul><ul><li>Boards </li></ul></ul><ul><ul><ul><li>Sheathing, siding, flooring, paneling, trim, patterned millwork </li></ul></ul></ul><ul><ul><li>Dimension Stock </li></ul></ul><ul><ul><ul><li>Light framing, joists, planks, roof & floor decking </li></ul></ul></ul><ul><ul><li>Timbers </li></ul></ul><ul><ul><ul><li>Posts, beams, stringers </li></ul></ul></ul>
    17. 17. MANUFACTURING PROCESS <ul><li>Trees are cut and transported to mill </li></ul><ul><li>Logs are cut into shorter lengths </li></ul><ul><ul><li>Cut to fit machinery or to certain length </li></ul></ul><ul><li>Logs are sent through debarker </li></ul><ul><ul><li>Bark is removed by peeling, scraping or blasting using high-pressure water jets </li></ul></ul><ul><li>Log is sent through a headsaw </li></ul><ul><ul><li>Circular saw or band saw </li></ul></ul>
    18. 18. MANUFACTURING PROCESS <ul><li>Rough cants, timbers, planks & boards are sent through an edger </li></ul><ul><ul><li>Removes rounded edges </li></ul></ul><ul><ul><li>Rips lumber into desired width </li></ul></ul><ul><li>Lumber is then moved onto trimmer </li></ul><ul><ul><li>Saws trim off rough ends & defects </li></ul></ul><ul><li>Next step is green chain, where edged, trimmed lumber are sorted visually </li></ul><ul><ul><li>According grade, species and size </li></ul></ul>
    19. 19. MANUFACTURING PROCESS <ul><li>Plainsawing: </li></ul><ul><ul><li>Better yield from the log </li></ul></ul><ul><ul><li>Cheaper (better yield) </li></ul></ul><ul><ul><li>Uneven grain patterns </li></ul></ul><ul><ul><li>Uneven shrinkage (warps) </li></ul></ul><ul><ul><li>Used for framing lumber </li></ul></ul><ul><li>Quartersawing: </li></ul><ul><ul><li>Less yield from the log </li></ul></ul><ul><ul><li>Expensive (less yield) </li></ul></ul><ul><ul><li>Even grain patters </li></ul></ul><ul><ul><li>Even shrinkage (no warps) </li></ul></ul><ul><ul><li>Used for trim lumber </li></ul></ul>Milling
    20. 20. Typical Sawing Method Typical Sawing of a Large Log
    21. 21. Typical Sawing Method
    22. 22. MANUFACTURING PROCESS <ul><li>After sawmilling, lumber is seasoned. </li></ul><ul><ul><li>Kiln-dried or air-dried </li></ul></ul><ul><li>Drying Effects </li></ul><ul><ul><li>Shrinkage </li></ul></ul><ul><ul><li>Reduced weight </li></ul></ul><ul><ul><li>Increase of strength and stiffness </li></ul></ul><ul><ul><li>More dimensional stable </li></ul></ul>
    23. 23. MANUFACTURING PROCESS <ul><li>Moisture Content: </li></ul><ul><li>Amount (percentage) of moisture (water) in the lumber </li></ul><ul><li>More moisture, more shrinkage!! </li></ul>Shrinkage creates problems!! A N D Seasoning
    24. 24. SEASONING- Shrinkage <ul><li>Heartwood: oldest and strongest part of the tree </li></ul><ul><li>More shrinkage PERPENDICULAR to the grain </li></ul><ul><li>Lumber defects </li></ul><ul><ul><li>Warps </li></ul></ul><ul><ul><li>Cracks in finish work </li></ul></ul><ul><ul><li>Checks </li></ul></ul>
    25. 25. SEASONING- Shrinkage <ul><li>Lumber Defects </li></ul><ul><ul><li>Crook </li></ul></ul><ul><ul><li>Cup </li></ul></ul><ul><ul><li>Twist </li></ul></ul><ul><ul><li>Bow </li></ul></ul><ul><ul><li>Splits </li></ul></ul><ul><ul><li>Checks </li></ul></ul>These are called seasoning defects
    26. 26.
    27. 27. SEASONING- Moisture Content <ul><li>Moisture content varies </li></ul><ul><ul><li>26-32% when cut </li></ul></ul><ul><ul><li>19% MAXIMUM for framing-”kiln-dried” </li></ul></ul><ul><ul><li>15% when shrinkage is a concern </li></ul></ul><ul><li>Over 19% moisture content is considered “GREEN” (not good…) </li></ul>
    28. 28. MANUFACTURING PROCESS <ul><li>Lumber is then sent to planing mill </li></ul><ul><ul><li>Sizing and surfacing </li></ul></ul><ul><ul><li>Then graded, tallied and prepared for shipment </li></ul></ul>Rough sawn (not surfaced) <ul><li>Purpose for surfacing </li></ul><ul><ul><li>Smooth </li></ul></ul><ul><ul><li>Dimensional precision </li></ul></ul><ul><li>Surfacing typically performed after drying </li></ul>
    29. 29. Additional Resources The Encyclopedia of Wood by: Aidan Walker <ul><li>Check out class WebCT site: </li></ul><ul><ul><li>Articles from Fine Homebuilding Magazine </li></ul></ul><ul><ul><li>Website links </li></ul></ul>

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