The method of cladding attachment is important to limit thermal bridging through the exterior insulation while adequately supporting the exterior cladding.

The vapour permeability of the sheathing membrane and exterior insulation should be carefully considered to avoid creating a risk of condensation within the assembly or reducing the ability of the assembly to dry in the event that incidental wetting occurs. In BC's climate zones, a vapour permeable exterior insulation in combination with an interior vapour barrier typically provides a lower risk wall assembly than does an assembly using impermeable exterior insulation.

See Insulation Ratios on Page 13 for more information and code reference.