Air Barrier vs. Vapour Barrier

AIR BARRIER CRITERIA

  • Impermeable to air flow
  • Installed anywhere in building envelope assembly
  • CONTINUOUS, by sealing all seams, edges, gaps, holes, etc.
  • DURABLE during construction and for the expected life of building
  • Rigid and strong enough to withstand air-pressure differences

VAPOUR RETARDER CRITERIA

  • Impermeable to moisture flow
  • Installed to the warm side of the insulation
  • Must cover as much surface area as possible, NOT CONTINUOUS
  • DURABLE during construction and for the expected life of the building
  • Not necessarily resistant to air flow