Condensation control in dwellings

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Condensation in dwellings occurs when warm moist internal air comes into contact with cold inside surfaces, or with cold air or surfaces within the structure.

With improved thermal performance and air tightness in new and existing buildings, the risk of damage from condensation has increased. Most surface condensation is largely caused by the behaviour of occupants, such as breathing, cooking and bathing - all emitting moisture. However, the designer can influence these effects by specifying suitable controls (such as mechanical ventilators) and reducing thermal bridging to enable the occupant to limit the incidence of surface condensation.

This Wood Information Sheet (WIS) explains the difference between surface and interstitial condensation and describes design measures to reduce the incidence of condensation.



  • Surface condensation
  • Interstitial condensation
  • Factors that affect condensation
  • Control of condensation
  • Design measures to reduce condensation
  • Properties, units and definitions related to water vapour in air and in materials


This Wood Information Sheet was reviewed in July 2017 and minor corrections were made.

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