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Exposure 1, Bond Durability

Durability Classification for US OSB Panels  – Exposure 1

All APA trademarked OSB panels are manufactured to Exposure 1 standards, which is equivalent to the European OSB/2 classification for load bearing panels for use in dry conditions.

Bond classification relates to moisture resistance of the glue bond and therefore the structural integrity of the panel. It does not relate to physical (erosion, ultraviolet etc.) or biological (mould, fungal decay, insect etc.) resistance of the panel.

  • Exposure 1 panels have the same adhesive as exterior plywood panels but are not suitable for long-term exposure to the weather.
  • They are able to resist the effects of moisture due to construction delays, or other conditions of similar severity.
  • OSB/2 is defined in EN 300: Oriented Strand Boards (OSB) – Definitions, classification and specifications.
  • Panels classified as Exposure 1/OSB/2 will not be adversely affected by moisture under the internal conditions of Service Class 1 or 2 environments as defined in Eurocode 5.  See more on Service Classes and moisture environments.