Engineered Wood Products (EWP)

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Engineered Wood Products(EWP)
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Definition

• A range of derivative wood products which are
  manufactured by binding strands, particles,
  fibers or veneers of wood together with adhesives
  to form a composite material.

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Characteristics

• Engineered wood products (EWP) are made form the
  same hardwoods and softwoods as dimensioned
  lumber.
• Similar products can be manufactured from other
  lignin containing materials such as straw, stalks
  or sugar cane residue.
• Engineered wood products can be used in almost
  every situation to replace dimension lumber.
• These products are engineered to precise design
  specifications, which are tested to meet national
  or international standards.

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Advantages of EWP

• EWP can be designed to meet application-specific
  performance and environmental requirements.
• Large panels of EWP can be constructed from small
  trees and/or small pieces of wood.
• Engineered wood products are often stronger
• More dimensionally stable.

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Disadvantages of EWP

• More expensive to produce.
• The adhesives that are used can be toxic and a
  pollution concern.
• Adhesives can outgas.

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Common EWP

• Glulam
• I-Joist
• Structural Composite Lumber
• Orientated strand board
• Plywood
• Siding
• Specialty wood products
• Nonstructural engineered wood products

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EWP-Glulam

• Glulam is a stress-rated engineered wood product
  comprised of wood laminations, or "lams," that
  are bonded together with strong, waterproof
  adhesives.
• Glulam components can be a variety of species,
  and individual "lams" are typically two inches or
  less in thickness.
• Uses
• Vertical columns
• Horizontal beams
• Complex shapes

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EWPGlulamcont.

• Complex shapes

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EWP-I Joist

• "I"-shaped engineered wood structural members
  that offer strength, versatility and economy for
  use in residential and light commercial
  applications.
• I-joists are comprised of top and bottom flanges
  of various widths united with webs of various
  depths.
• The flanges resist common bending stresses, and
  the web provides outstanding shear performance.

• EWP I-joists can be closed

or open
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EWP- Structural Composite Lumber

• Structural composite lumber (SCL) is a family of
  engineered wood products created by layering
  dried and graded wood veneers or flakes with
  waterproof adhesive into blocks of material known
  as billets.
• SCL includes
• Laminated veneer lumber (LVL)
• Laminated strand lumber (LSL)
• Oriented strand lumber (OSL)
• Cured in a controlled process, SCL is typically
  available in various thicknesses and widths and
  is easily worked in the field using conventional
  construction tools.

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EWP-Oriented Stand Board (OSB)

• OSB is manufactured from waterproof heat-cured
  adhesives and rectangular shaped wood strands
  that are arranged in cross-oriented layers,
  similar to plywood.
• This results in a structural engineered wood
  panel that shares many of the strength and
  performance characteristics of plywood.
• Produced in huge, continuous mats, OSB is a solid
  panel product of consistent quality with no laps,
  gaps or voids.

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Plywood

• Laminated product.
• Thin sheets of veneers (piles) are peeled from a
  log.
• Each pile is rotated 90 degrees.
• The piles are glued and bonded under heat and
  pressure.

1http//www.apawood.org

• Most common construction is three, five or seven
  piles.
• Most common size is 4 ft x 8 ft.

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Types of Plywood

• Types of plywood are categorized by six (6)
  grades of the veneers and four (4) bonding types.
• Six (6) veneer grades (Fig 40-11)
• A smooth, paintable. No more than 18 neatly made
  repairs
• B Solid surface. Repairs and tight knots up to 1
  inch permitted
• C Tight knots to 1-1/2 inches. Discoloration and
  sanding defects, limited splits
• C (Plugged) Improved C veneer.
• D Knots and knotholes to 2-1/2 inches. Limited
  splits allowed. Limited to interior panels.

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Four (4) Plywood-Bonding Types

• Interior Plywood
• Plywood for interior use only are made from
  various hardwood and softwood species, and can be
  used only in interior applications such as wall
  sheathing, furniture (where exposure to moisture
  is limited), cabinetry and the like.
• Interior plywood is available in most grades, as
  well as a number of hardwood species such as
  birch, oak and cherry.
• Exterior Plywood
• The most common type of plywood, readily
  available at home centers.
• The glues used in exterior plywoods are much more
  resistant to moisture than interior plywoods.
• Once again, nearly all grades are available, with
  A-C, B-C and CDX the most common. Numerous
  hardwood species are also available in exterior
  varieties.

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Plywood Bonding Types-cont.

• Marine Plywood
• When moisture resistance is a priority, look into
  marine plywood.
• This type uses the best adhesives and is
  manufactured to the highest standards.
• It also is most commonly graded as A-A, with two
  top grade faces, but is limited in the hardwood
  choices that are practical for use in marine
  settings.
• Structural Plywood
• When the appearance of the face is of lesser
  concern than the strength and stability of the
  material, structural plywood will typically be
  the choice.
• The resins used to adhere the plies are designed
  for extra strength to avoid separating of the
  layers.
• Structural plywood is seldom found in a grade
  higher than C-D. It is commonly used in concrete
  forms on construction sites.

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EWP-Siding

• A single layer of rack-resistant panel siding
  delivers an attractive exterior appearance while
  eliminating the labor and materials cost of
  installing separate structural sheathing.

Engineered siding products are a popular
alternative to wood, vinyl, and aluminum siding.
Engineered wood products may include cement, or
other materials, to produce an authentic
appearance without the maintenance and expense of
natural wood.
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EWP - Specialty Wood Products

• Engineered wood can be used in thousands of
  different applications.
• Some of these applications are made possible
  though the creations and innovations
  manufacturers
• Engineered wood products with unique
  characteristics are suitable for building diverse
  end-use products such as boats, truck bodies and
  even upholstered furniture.

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EWP - Specialty Wood Productscont.

• FRP (Fiberglass-reinforced-plastic) plywood
• SIP (Structural Insulated Panels)

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EWP- Nonstructural Engineered Wood Products

• Medium density fiberboard (MDF)
• Particle board

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Medium Density Fiberboard (MDF)

• MDF is manufactures by breaking down softwood by
  rubbing it into wood fibers.
• The fibers are combined with wax and resin,
  formed into panels and solidified with
  temperature and pressure.
• It has higher density than normal particleboard.

Biggest concern is the use of formaldehyde
resins. Will disintegrate with water.
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MDF Characteristics

• Should not be used outdoors because it will swell
  upon contact with water.
• Consistent structure
• Easy to machine.
• Can also be used with veneers.
• Good material for cabinets and acoustic
  enclosures.

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Particleboard

• Also called chipboard.
• Manufactured from wood particles larger than what
  is used for MDF.

• Characteristics
• Cheaper, denser and more uniform the dimensioned
  lumber and plywood.
• Best used when appearance and strength are less
  important than cost.
• May be veneered
• Prone to expansion a discoloration due to
  moisture.

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Roofing Siding

• Manny different materials can be used, but steel
  and aluminum sheets are popular for agricultural
  buildings.
• Different thicknesses
• Different quality of paint/galvanizing.
• Roofing materials (Fig 40-15, pg 583)

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Siding Materials

• Popular siding materials for Ag buildings

• Wood
• Steel
• Aluminum
• PVC
• Polypropylene
• Composite
• Masonry

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Questions