AS 4654.2 stipulates the requirement for upward vertical termination height of an external waterproofing membrane. The height requirement ranges from 40 mm to 180 mm depending on the building’s wind class. Note that this is the height required above finished floor level.

A building’s wind classification (AS 4055) can be calculated in accordance with AS 1170.2 which sets out 4 primary factors for determining a building’s wind class determination:

  1. Geographic wind speed region
  2. Terrain category
  3. Topography
  4. Shielding

A guide to calculating wind class can be found here but calculations should be undertaken by an engineer familiar with AS 1170.2.

Remember this height is the height above finished floor level. Falls have to be calculated before membrane application to determine the expected finished floor level height – so it’s known how high to continue the membrane up the wall. See How do I calculate finished floor level?