From the 1st May 2019, all building permits require the use of a pliable vapour permeable membrane in Australia climate zones 6, 7 and 8. The code change was imposed because of the risks of condensation in wall cavities.

For class 1, 2 and 4 building permits approved after the code change, a vapour permeable membrane must be used on the external wall. A detailed map of the affected zones and regions are included in this brochure.