Investigation of the heat and moisture performance of naturally ventilated wall systems in residential buildings in Australian climates

Managing moisture in buildings has become increasingly important, as the recent drive for building energy performance has resulted in increasingly complex building envelopes. Cavity ventilation is a potential solution to both manage moisture and improve building thermal efficiency. This thesis investigates the impacts of ventilated cavities on the hygrothermal performance of lightweight wall constructions in residential buildings in Australian climates. A semi-analytical cavity ventilation model was developed and used in combination with one-dimensional hygrothermal simulation tool WUFI Pro to calculate transient cavity ventilation rates and simulate the hygrothermal performance of walls in four case studies that investigated: 1) a comparison of constant and transient cavity ventilation rates, 2) the impact of cavity entrance and exit opening widths, 3) the impact of cladding colour, and 4) the impact of additional insulation materials. Four cardinal wall orientations were investigated across five locations in Australia representing different climates: Melbourne, Sydney, Sunshine Coast, Cairns, and Alice Springs. Simulation results were assessed by comparing: 1) cavity ventilation rates, 2) heat gains and losses to the indoor space contributing to heating and cooling loads, and 3) mould risk over 10 years.