A-9.25.5.1.(1)(a)(ii) Reduced Potential for Condensation in the Building Envelope.

The requirements in Article 9.25.5.2. aim to reduce the risk of condensation being introduced into wall assemblies due to the water vapour permeance of the outboard materials. Research has confirmed that the reduced condensation potential of exterior continuous insulation with a thermal resistance of at least 0.7 (m2 ·K)/W and a water vapour permeance between 30 and 1 800 ng/(Pa·s·m2) compares to reference assemblies without exterior insulation in a given geographic location and climatic exposure.