Establishing an environmentally controlled room to quantify water vapour resistivity properties of construction materials

In Australia, the National Construction Code recently included the first performance requirements relating to condensation risk mitigation in Australian Buildings. Furthermore, it’s expected that further enhancements to these regulations will occur in 2022, 2025 and 2028. Hence, hygrothermal performance assessment, which is the method by which water vapour pressure is simulated becomes an important part of the statutory process. To undertake a hygrothermal simulation relies upon building materials database, which includes water vapour resistivity, conductivity and water absorptivity properties. At this stage, whilst many materials used in Australian construction may have published values for conductivity and absorptivity, very few products have published values for water vapour resistivity. Additionally, manufacturers of building materials used in the external envelope of buildings will be seeking guidance about the water vapour resistivity properties of their products. This paper discusses the research which has been completed to establish Australia’s first laboratory to test the water vapour resistivity of building materials. The methods proposed include the use of a conditioned test room and an environmental chamber. This paper focuses on the establishment of an environmentally controlled test room for quantifying materials’ water vapour resistivity through gravimetric method. The establishment and operation of the environmental chamber will be reported later.