Permeable Building Wrap, NCC 2019, Condensation Management

Are you a house builder or energy rater?

BCA 2019 Volume Two (Class 1 houses), Clause 3.8.7.2 requires that if a pliable building membrane is installed (building wall wrap) it must be a vapour permeable membrane for Climate Zones 6, 7 & 8.

In Sydney imagine a line from Berowra, Hornsby, Castle Hill, Parramatta, Milperra, Lucas Heights & Heathcote to the west of this is Climate Zone 6, wall wraps must be permeable to reduce risk of condensation occurring.

  • Standard sarking is not permeable at  0.01 μg/N.s (poor)
  • AS 4200.1 minimum requirement 0.14 μg/N.s (low permeability)
  • James Hardie Wall Wrap 2.2 μg/N.s (very good)
  • Proctor RW 4.5 μg/N.s (excellent)

James Hardie wall wrap is also a reflective barrier which suits a temperate climate like Sydney.

Proctor RW is not reflective which would be a better choice in a colder climate like Blue Mountains or Southern Highlands.

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