SR60 An anatomy of mildew risk with reflective insulation (2007)

This document attempts to allocate the contribution of different structural and operating features to the risk of mildew growth on the inside surface of lightweight external walls in New Zealand housing.

It presents a quantitative method based on predicted RH on the wall surfaces, suitable for a wide range of lightweight walls. These make allowance for local positional effects within a room.

The method makes use of the temperature index, which is amenable to routine assessment during insulation testing. The method is illustrated by its application to three light timber-framed walls of different insulation grade and predicts low mildew risk for insulated walls and about equal risk for reflective-insulated and uninsulated walls.