Engineered Wood Products (EWP)

1. Engineered Wood Products(EWP)

2. 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.

3. 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.

4. 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.

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

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

7. 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

8. EWP—Glulam—cont. Complex shapes:

9. 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

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. 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.

18. EWP - Specialty Wood Products—cont. • FRP (Fiberglass-reinforced-plastic) plywood • SIP (Structural Insulated Panels)

19. EWP- Nonstructural Engineered Wood Products • Medium density fiberboard (MDF) • Particle board

20. 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.

21. 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.

22. 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.

23. 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)

24. Siding Materials • Wood • Steel • Aluminum • PVC • Polypropylene • Composite • Masonry • Popular siding materials for Ag buildings:

25. Questions