Plywood is composed of at least three elements: a face, a back and a core. Holding these pieces together is the glue line or glue. Each type of core has a specific use and represents a better value or better product for the specific use. The most common type of core used prior to World War II was veneer core.

Veneer Core Plywood - Figure 200-06 from AWI Quality Standards. Seventh Edition.
  • Veneer Core: Layers of veneer are pressed together in alternating perpendicular layers balanced on either side of a central core layer. This type of plywood is more prone to surface irregularities and defects, but it exhibits greater strength in bending and in stress than the other core types.

  • Particleboard Core Plywood - Figure 200-04 from AWI Quality Standards, Seventh Edition
  • Particle Core or Chip Core: Particle core is produced in alternating perpendicular layers balanced on either side of a large plants on a continuous press line from wood chips, glue and resins and then cut up into panels. Its surface is smooth, but some small voids are always present.

  • Medium Density Fiberboard Core Plywood - Figure 200-05 from AWI Quality Standards, Seventh Edition
  • Fiberboard: Fibeboard is the flattest and smoothest core for plywood. Medium density fiberboard (MDF) makes a superb carrier for veneer. It has few surface imperfections or voids and is dimensionally stable and flat.

  • Lumber Core Plywood - Figure 200-07 from AWI Standards, Seventh Edition
  • Lumber Core: Lumber Core is manufactured from thin strips of lumber glued on edge and covered by veneer crossband perpendicular to the core's grain direction. When lighter cores are required to specific strength in one direction is required, lumber core is often used.

  • Fire-Retardant Core- Figure 200-01 from AWI Quality Standards, Seventh Edition.
  • Fire Retardant Cores: Fire Retardant Cores are usually made of particle core with fire resistant salts added to the chips and glue when pressed. In many cases, fire rated cores are required for paneling in entries, lobbies, and areas of public spaces. This type of core is weaker and more prone to expansion and contraction than standard particle core or medium density fiberboard. Fire rated veneer core is usually less flat and prone to warping. Fire rated medium density fiberboard is not as available as fire rated particle core.

  • Combination Core Plywood - Fiture 200-08 from AWI Quality Standards, Seventh Edition
  • Engineered Wood Cores: Engineered wood is a new type of core utilizing the strength and lightness of veneer core, but having improved flatness, rigidity and dimensional stability. The core is made of linear strips of thick fibrous veneer glued and pressed together in an irregular pattern.
  • Water Resistant Cores: Water Resistant Particle Core, Water Resistant Veneer Core and Waterproof Veneer Cores are avilable. The Architectural Woodwork Institute Quality Standards require that all Premium Grade tops made for use in wet areas, such as near a sink, be made from water resistant or waterproof cores.

  • Veneer Core.

    Particleboard Core.

    Medium Density Fiberboard Core.

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