wood construction. wood hardwood: deciduous oak, maple, walnut fine carpentry softwood: coniferous...
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WOOD CONSTRUCTION
WOOD
Hardwood: deciduous• Oak, maple, walnut
• fine carpentrySoftwood: coniferous (cone bearing)
• Pine, spruce, fir
• outdoor
WOOD DECAY
Decay requires:• Food (wood)• Moisture
MOISTURE CONTROL
• Susceptible wood should be 8" above soil
• 5% grade from house out 10'• Downspouts 10' away from house
MOISTURE CONTROL
• Shrubs should be 5' + 1/2 the mature diameter away from house
MOISTURE CONTROL
• Crawlspace crowned and covered with plastic
NATURALLY DECAY RESISTANT WOOD
CEDAR• Fragrant• Structurally weak
NATURALLY DECAY RESISTANT WOOD
CEDAR• Commonly 1x dimensions
NATURALLY DECAY RESISTANT WOOD
CYPRESS• Good structural• Commonly 1x dimensions
NATURALLY DECAY RESISTANT WOOD
REDWOOD• Natural red color• Good structural• Expensive • Heartwood most resistant (versus
sapwood)
NATURALLY DECAY RESISTANT WOOD
COMPOSITE WOOD• Hardwood sawdust and reclaimed
plastic• Very durable, good longevity• No splinters• Expensive
NATURALLY DECAY RESISTANT WOOD
IPE (EE-pay)• Tropical wood• Extremely dense (drill holes for nails)• Decay and fire resistant• Does not float
PRESSURE TREATED WOOD
• Wood susceptible to decay• Forcing chemical preservatives into
wood under high pressure• Copper-containing (ACQ)
• Safest available• Arsenicals (Not common anymore)
• Chromated copper arsenate (CCA)• Health concerns
• Creasote• Railroad ties
PRESSURE TREATED WOOD
• Concentration ratings•0.40 -- ground contact (pounds per
cubic foot)
PRESSURE TREATED WOOD
SOUTHERN YELLOW PINE• Structurally strong• Dense• Very susceptible to warping and
shrinkage
PRESSURE TREATED WOOD
• Do not burn, toxic fumes• Avoid prolonged inhalation of
sawdust• Wash after prolonged exposure
WOOD SIZE
• Nominal size: actual dimension of wood at the cutting mill
• Actual size: after milling (shrinkage and planing)• 1" and less: 1/4"• 2" to 6": 1/2"• 8" and above: 3/4"
COMMON DIMENSIONS
• Lengths: 6', 8', 10'...• Thickness and width• 2" bys (2x4, 2x6, 2x8, 2x10 or 2x12)• 4" x 4" or 4" x 6"• 6" x 6"
COMMON DIMENSIONS
• PLYWOOD: thin layers of wood glued together
• 4'x8' sheets• Thickness: 1/4", 1/2", 3/4", 5/8"...• Exterior grade
GRADING: QUALITY
• SELECT and NO. 1 high grades•No. 2 commonly used
GRADING: MOISTURE
• Moisture content• Dried to less
than 19% moisture to avoid rot (s-dry)
• >19% is green wood (s-grn)
GRADING: OTHER
• Mill• Grading
association• Species
GRAIN
• Growth rings created by different growth rates throughout year
• Springwood: lighter band an softer• Summerwood: dark and dense• Fine grain: rings close together (slow
grower)• Coarse grain: rings far apart
HEARTWOOD• Inner, inactive portion of trunk• Plugged off and high resistance to rot
SAPWOOD• Outer layer still active• Not as decay resistant or structurally
sound
QUALITY
• Warping, bowing, cupping, splitting
Knots• Result of limbs• Reduces strength and workability
STORAGE
• Off ground• Stacked neatly • Covered and out of direct sun