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- BC History
- Prehistoric: used for shelter and tools
- Neolithic Era: cut trees used for shelter (Pithouse, Longhouse, Tipi) and joined cutting / notching to interlock parts (secure with wood pins)
- 3rd: Romans forge first nails
- AD History
- 607: Japanese beam and bracket system
- 5th: Half-timbering
- 1800s: Water powered saw mill
- 1833: Balloon framing (Augustine Taylor)
- 1860: Arts & Crafts movement
- 1900s: Glue-laminated Timber, England
- 1945: Platform framing
- 607: Hry-Ji Temple, Nara Beam & Bracket System (beam & bracket)
- 1097: Westminster Hall, London (half-timbering)
- 12th: Norwegian Stave Churches (Half-timbering)
- 1833: St. Mary's Church, Chicago (Taylor) (balloon framing)
- 1908: Gamble House, CA (Green Brothers)(craftsman bungalow)
- 1930: Laminated arches
- 1965: Sea Ranch Condominiums (Charles Moore) (shingle style w/ angles)
- 1980: Thorncrown Chapel, Arkansas (Fay Jones) (lightweight wood and glass)
- Only material that is renewable.
- Not precise due to organic nature.
- Specify local certified forest products
- Specify standard size sheets and lengths
- Integrated with rubber, plastics or adhesives
Hard fibrous substance lying beneath the bark of trees.
Wood that has been sawn into construction members.
Lumber that is 5" or larger in its least dimension.
- Softwood: from evergreen trees
- Hardwood: from deciduous trees
- 70% Cellulose; 18-28% Lagnin
- Most accommodating construction material
- Readily available
- Easy to work with
- Lower Cost
- Stronger in compression than tension
- Differs per direction
- Strength when load is applied parallel to the grain
- Shear strength when load is applied perpendicular to the grain
Wood that is living and contains a large amount of water.
- Lumber dried out to reach a specified moisture content for use in construction.
- Stronger (as building material and for fasteners)
- More resistant to warping, decay, and insects
- Hold paint
A method of seasoning lumber which takes several months and leaves 10-20% moisture.
A method of seasoning lumber which takes a few days and leaves 10% > 0 moisture.
Framing Lumber: 0<19% seasoned
FIBER SATURATION POINT
- Point at which wood shrinks, swells, and resists decay.
- Effects shrinkage, distortion, and warping.
- Most shrinkage: Tangentially (direction of growth rings)
- Medium shrinkage: Radially (across growth rings)
- Little shrinkage: Longitudinally (parallel to the grain)
Hardwood Cut Types
- Plainsawed: tangent to the annual rings (0-45 deg to the wide face)
- Quartersawed: radially to the rings (45-90 deg to the wide face)
Softwood Cut Types
- Flat-grained (slash-grained): tangent to the annual rings.
- Edge-grained (vertical-grained): radially to the rings.
- Distinct grain pattern
- Uneven wear, twisting or cupping
- Raised grain
- Shrinks and swells in width (less in thickness)
- Less cutting waste
- Even grain pattern
- Even wear with less warp
- Shrinks and swells in thickness (less in width)
- More cutting waste
- More cost
Flaws in lumber that affect the strength, appearance, use and grading.
Defects resulting from natural causes.
Types of Natural Defects
- Knot: a branch embedment in a tree that was cut through when manufactured
- Peck: pitted area found in cedar and cypress
- Pitch Pocket: opening between growth rings containing resin
- Shake: lengthwise grain separation between or through growth rings
Defects arising from seasoning or processing of lumber.
- Uniform standard of quality given to lumber based on appearance or strength of its end use.
- Best grades have almost no imperfections.
- (Stress Grading)
- Visual: based on the number, size, type and location of visible defects
- Machine: lumber subjected to computation of bending, values of the modulus of elasticity (E) and allowable fiber stress (f)
Established by the National Bureau of Standards according to use, size and manufacturer.
Softwood Use Classification
- Yard Lumber: used in general construction
- Factory and Shop Lumber: used for remanufacturing into other products and based on the amount of clear wood in each piece.
Softwood Lumber Size Classifications
- Boards: 2" < wide; <2" thick;
- Dimensional Lumber: 2" < wide; 2-5" thick
- Timbers: 5" < wide and thick
- Graded on: Appearance
- Used: siding, subflooring, trim
- Select classification: A to D (A is of highest quality / natural finish)
- Common classification: 1 to 5 (1 is fewer blemishes)
- (Structural Lumber)
- Graded on: Strength and size
- Used: load-bearing members
- Size classification: joists and planks; light framing; decking
- (Structural Lumber)
- Graded on: Strength and size
- Used: load-bearing members
- Size Classification: beams and stringers; posts and timbers
Softwood Manufacture Classification
- Rough: visible saw marks
- Dressed: planed smooth to uniform sizes
- Worked: dressed and then tongue-and-grooved, shiplapped, or shaped to a pattern
- Based on the amount of clear, usable lumber in a piece.
- Standard grades: 1st; 2nd; Selects; Sound Wormy; Common #1, 2, 3A, 3B
- Lumber is specified in nominal (rough) dimensions.
- Lumber is measured in board feet (1"x12"x12" length)
Manufactured wood panel consisting of several alternating grain, thin wood veneer sheets (plies) that are permanently bonded together with adhesive under high pressure.
- Individual panels of plywood
- Usually odd number: 3, 5, or 7
- Face / Back: Outer plies (grain parallel to long dimension)
- Core: Center ply (solid lumber or particle board)
- Crossbands: Plies located between outer and center plies
- Veneers are rotary cut (except when hardwood grain face is important)
- 4x8 sheets
- 5/16" to 1 1/8" thickness
- Backing for finish materials
- Sheathing (wall, floor, and roof)
- Classified by: type of adhesive used; species of veneer face (softwood or hardwood)
- Interior: moisture-resistant
- Exterior: waterproof
- Graded by: Quality of the veneers
- Designation: (2) letters (A-D); face and back
- Exterior plywood: uses grade C or better for inner plies
- Interior plywood: uses grad D or better inner plies
- Group #: identifies wood species (1 to 5); 1 = strongest and stiffest
- Identification for plywood used as sheathing or subflooring.
- 2 #'s: X/Y (X = maximum recommended roof span in inches) (Y=maximum recommended floor span in inches)
- Book Matching (edge Matching): panel is flipped to mirror grain
- Slip Matching: panels laid side by side repeating grain pattern
- Random Matching: panels grains are purposely unmatched
- Strength in both directions
- Resistance to lateral loads (wind or earthquake; roof, floor, shear wall)
- Resistance to shrinking and splitting
- Less warpage
- Covers large surface area
- Hardwood plywood is more expensive and used decoratively.
Other Plywood Types
- Overlay: covered with a resin-fiber overlay
- Marine: used for marine applications
- Prefinished: stained and ready to use
- Patterned: grooved, roughsawn, etc.
- Made from wood fibers that have been highly compressed under heat and pressure into dense, durable boards.
- Categories: Basic; Prefinished (baked enamel, plastic laminate)
- Types: Tempered; Standard; Service Standard
- Size: 4x8 sheets; 1/8" to 3/8" thick
- Use: Exterior siding; soffits; interior walls; ceilings; cabinetry; pegboards; acoustical treatment
- Manufactured from waste paper, wood pulp and fibers.
- Size: 4x8 sheets; 1/2" to 1" thick
- Fiberboard roof insulation and decking (2x4 sheets)
- Use: Acoustical tile; sheathing; interior wall finish; roof insulation; laminated decking
- Composed of large wood flakes bonded together with synthetic resins under pressure.
- Properties: lightweight; good insulation value; good acoustic value; damaged easily
- Use: insulating backup material on upper walls and ceilings
- Dry-formed wood particles bonded together with synthetic resin.
- Use: core stock for plastic laminate or hardwood veneers, manufacture of furniture, countertops, wall paneling, doors
- An insulating board consisting of a core of small, expanded polystyrene beads with heavy paper laminated to both sides.
- Use: Foundation perimeter insulation material.
- Layers of phenolic-resin kraft paper, patterned sheet, and melamine resin treated paper fused with intense heat and pressure and used as a finish material.
- Use: Adhered to plywood for countertops, wall coverings, and furniture
- Structural members fabricated from layers of wood that are bonded with adhesives in which all layer grains are parallel longitudinally.
- Lamination thickness: 1 1/2" (3/4" for small radius curves)
- Standard widths
- Range of depths up to 75"
- Single Tapered - Straight
- Double Tapered - Straight
- Double Tapered - Curved
- Double Tapered - Pitched
- Graded by: Appearance
- Industrial: Lowest; appearance of little concern
- Architectural: Medium; appearance of important concern
- Premium: Highest; appearance is of primary concern; most expensive and arrives to site wrapped
- Type of Adhesive: Interior or exterior
- Stress Grade Required
- Appearance Grade
Individual laminations are joined to achieve full required member length.
A glulam joining method consisting of splices on the top and bottom face of opposing members to create one seam on each face.
A glulam joining method consisting of v-shaped cuts along the end of members allowing an interlocking joint.
- Factory produced to have better quality control
- More dimensionally stable
- Weather resistant
- Consistent size, appearance, strength
- Longer spans
- Supports heavier loads
- Material manufactured from layers of kiln-dried lumber that are bonded with adhesives.
- 3-5" thickness
- Standard lengths
- Interior surface is exposed and can be smooth, grooved, prefinished, stained
Destructive insects that cause damage to wood by eating it from the inside in warm, humid climates.
- Proper drainage to minimize moisture
- Good ventilation
- Impervious concrete foundations
- Shields: Metal strips used to prevent insects from reaching the wood.
- Penetrating preservatives
- (methods effective for carpenter ants)
Marine Boring Organisms
Organisms which damage wood located in salt water.
Apply heavy treatment of creosote preservative.
Destruction of wood caused by fungi developed from mild temperatures, moisture, and air, feeding on the cell walls.
- Keep wood dry
- Ensure ventilation
- OR keep continually submerged in water to avoid air
- Specify decay resistant wood (redwood)
- Pressure treat with preservatives
Destruction of wood from burning (except heavy timber)
- Chemical solution injections into the wood (ammonium phosphate)
- Surface treatments (intumescent paint, spraying, encasing)
A treatment that is applied to wood which retards the increase of temperature and reduces the rate of flame spread.
- Chemicals controlled by regulations which protect wood from hazards.
- Oil-born Solutions: discoloration or oily surface difficult to paint (Creosote)
- Waterborne Solutions: Chromated Zinc Chloride
- Applied by: brushing, spraying, dipping, pressure for deeper penetration
- Rigid Frames
- Built-up Girders
- Glulam beams
- Trussed Rafters
- Plywood Girders
- Stressed Skin Panels
- Balloon Framing
- Platform Framing
- Post and Beam
- Continuous wall studs from the foundation to the top plate beneath the rafter.
- 2 stories max in height
- Single story studs with floor joists bearing on the top plate of the wall below.
- Multiple stories in height
Post and Beam
- Beams rest of columns to carry the floor or roof loads down to the foundation.
- Skeletal frame forms modular grid
- Lateral stability provided with rigid connections and enclosing exterior walls
- Connections made between members to ensure a stable structure.
- Mill / Shop
- Exterior: consider weathering
- Interior: consider appearance
- Structural joints must meet structural requirements
- The more invisible the joint the more expensive
- Species of wood
- Characteristics of wood
- Moisture content
- Appearance desired
Lap; shoulder; rabbet; miter; shoulder miter; quirk miter; T & G; T&G miter; butt; shiplap; spline; fillet; v-joint; batten; squared splice; splice; scarf; mortise & tenon; dado; dovetail; open joint; metal joint; metal u joing; open joint with filler
- Nails (most common)
- Metal connectors
- Most common method of fastening joints
- Driven into wood with a hammer or mechanical gun.
- Common Nails: structural connections
- Box Nails: thinner having less holding power
- Finish Nails: thin nails with small heads for attaching trim
- Items fabricated in a mill and delivered to the job site ready for installation. (shop fabricated)
- Protect with a primer / sealer before leaving shop
- Handle with care on jobsite to prevent warping or opening of joints
- Installation requires ventilation to avoid decay or dry rot.
- Ornamental shapes and molding fabricated from the better grades of softwood, hardwood or wood composites fused together with plastic binders by means of heat and pressure.
- Covers joints where two elements meet and are likely to pull away from each other.
- 1/4 round
- 1/2 round
WOOD SIDING / PANELING
- Sheets made from common dimensional lumber, cut and dressed to standard sizes, and variety of shapes and species.
- Siding: made from seasoned softwood
- Paneling: made from softwood or hardwood
- Only better grades are used
- Finished by: staining, painting or natural weathering
Siding / Paneling Types
- Vertical: Channel; Board & Batt; Tongue & Groove; Shiplap
- Horizontal: Bevel; Rabbeted Bevel; Vee Joint T&G; Drop T&G
- Light-Framed Construction: thin closely spaced
- Heavy Timber: heavy members configured as post & beam
- Design modules of 2 & 4ft (accommodate sheathing sizes)
- Strong woods: Doug Fir; Larch; Hemlock; Southern Pine
- Ave. Strength: No. 2 grades (Hem-fir; Spruce-pine-fir)
- Deflection limitations: l/240 & l/360
- Stress grades: #1, #2, #3 or SS