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UNIT 5 -Construction Lumber

UNIT 5 -Construction Lumber. Construction Lumber. Hardwood. Softwood. Hardwood. Deciduous Trees such as Oak, Locust, & Maple. Rarely used in Landscape Construction, because of checking, splitting, and discoloration. Less resistance to rot, due to lower levels of oils and resins.

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UNIT 5 -Construction Lumber

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  1. UNIT 5 -Construction Lumber

  2. Construction Lumber Hardwood Softwood

  3. Hardwood Deciduous Trees such as Oak, Locust, & Maple. Rarely used in Landscape Construction, because of checking, splitting, and discoloration. Less resistance to rot, due to lower levels of oils and resins. Some exceptions are Teak, Black Locust, & Cypress. Oak is often used as railroad ties then coated with creosote as a preservative.

  4. Softwood Coniferous Trees such as Yellow Pine, Douglas Fir, Cedar, & Redwood. Widely used in Landscape Construction, because of their “softer” qualities. Softwoods are easier to machine and paint. Resistance to rot, due to higher levels of oils and resins.

  5. Softwood Types Cedars – Weakest softwood, easy to machine, does not hold nails well, Rot resistant and weathers to natural gray, Readily available and moderately expensive. Douglas Fir – Moderately hard, difficult to work with, does not take paints well, moderate rot resistance, requires stain or preservative, Readily available and moderately expensive.

  6. Softwood Types Southern Yellow Pine – Hard & dense. Strongest wood used. Hard to machine, does not take stain and paint well. Will shrink and warp due to excess moisture and oils. Treated to resist rot, can be stained. Widely available in many sizes and shapes. Least expensive. Redwood – Strong and moderately dense. Most versatile, easiest to work with and stain. Highly rot resistant, Weathers to uniform gray. Most difficult to find and most expensive.

  7. Chromated Copper Arsenate • Saw, sand, and machine CCA-treated wood outdoors, when possible. Wear a dust mask, goggles, and gloves. • Clean up all sawdust, scraps, and other construction debris thoroughly and dispose of in the trash (i.e., municipal solid waste). • Do not compost or mulch sawdust or remnants from CCA-treated wood. • Do not burn CCA-treated wood, as toxic chemicals may be released as part of the smoke and ashes. • After working with the wood, wash all exposed areas of your body, especially the hands, thoroughly with soap and water. • Wash your work clothes separately from other household clothing before wearing them again.

  8. Wood Alternatives Plastic lumber is an increasingly popular building material. Plastic lumber, which is most frequently composed of high density polyethylene (HDPE), does not release hazardous materials into the ground. An additional benefit of using this material is that it is often manufactured with recycled plastic. Therefore, using plastic lumber conserves natural resources. In addition, plastic lumber usually requires less maintenance.

  9. Wood Alternatives Composite lumber - Wood and plastic combined into one lumber product is called composite lumber. Wood/plastic composites generally exhibit low moisture absorption and high resistance to decay, insect, and UV ray damage. The wood component provides the composite with greater dimensional stability than plastic lumber, but not as much as wooden lumber. Like plastic-only lumber, wood/plastic composite lumber is often made with recycled materials. Alternatives to CCA

  10. Lumber Grades Select Grade A – Best – clear Lumber Grade B – Blemish Free Grade C – Small Defects Grade D - Utility ( knots under ½”)

  11. Lumber Grades Common No. 1 – Sound Knots No. 2 – Loose Knots No. 3 – Large Knots, Bark edges No. 4 & 5 – Poorest wood quality

  12. Plain or Quarter Sawn?? In Plain sawing the cut is made tangent to the growth rings. This method yields the maximum number of cuttings with minimal waste. Wood cut in this manner is more prone to warp.

  13. Plain or Quarter Sawn?? In quarter-sawing the cut is made radially to the annual rings. The log is cut into quarters, then towards the center. This method is more wasteful, therefore more expensive, but is less distorted by warping. It also reduces checking and splitting.

  14. Rough Cut Lumber Rough cut lumber is defined as its name implies. Rough cutting is the first machining of a log into nominal dimensions. EX 2X4, Its appearance is actually “ROUGH” in so that it is not suitable in landscape construction for aesthetic reasons. It is also not recommended for exterior applications, because it will not take paints and stains well and will have little rot resistance.

  15. Dimensional Lumber Dimensional lumber is Rough cut lumber which has been surfaced on all sides. This surfacing removes part of the lumber making it smaller than it’s original size. Typically this surfacing removes about ¼” per side. This makes dimensional lumber about ½” smaller in width and height. EX. 2X4 is actually 1.5”X3.5”

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