Deemed-to-comply wall requirements in the 2010 Building Code of Australia
Authors: Daniel, Lyrian; Williamson, Terence
ABSTRACT: The recent 2010 update of the Building Code of Australia (BCA) increased the energy
efficiency requirements for all new commercial and residential buildings. The revised Code sets more
stringent requirements for all elements covered by the deemed-to-comply provisions, for example,
thermal resistance requirements for roof/ceiling, wall and floor elements. The BCA 2010 specifies the
required R-value for walls as a function of location in relation to climate but also allows for modification
of this value for walls of higher thermal mass, however the reasons or logic for these ‘thermal mass’
allowances have never been documented by the Australian Building Codes Board (ABCB). The first
part of this paper investigates the background and provides possible explanations for the allowances.
The likely effectiveness of these wall provisions are then assessed using the AccuRate thermal
performance computer software. Variations in construction are tested to ascertain the resulting effects
on the proposed m-factor. The paper concludes with a summary of findings and suggests that the
methodology could provide a basis for future editions of the BCA. Further research will include
sensitivity testing the methodology and applying it to different construction configurations.