Green Rate was appointed by the Nillumbik Mudbrick Association (NMA) earlier this year to conduct a study which will help determine the viability and potential costs involved in building a 6 Star mud brick home.

The study, funded by Sustainability Victoria, involved thermal energy assessments of four typical mud brick house designs using the FirstRate 5 house energy rating software. Caleb Young, Green Rate’s principal energy assessor, looked at simple and cost effective ways to take each design up to 6 Stars while maintaining each building’s unique character.

All four designs successfully achieved the 6 Star target, however, some proved more difficult than others. In most cases, double glazing was required to the living areas of each home as a minimum, and higher levels of insulation was needed in the ceiling/roof. The more difficult cases benefited greatly from an insulated slab-on-ground or ‘waffle pod’ slab, and higher performance double glazing incorporating low-e coating and argon gas filled cavities.

One design was able to score an extra 1.2 stars by reducing the length of the northern eave to allow greater solar access in winter. This house was the only one in the study to achieve the 6 Star target without using any double glazing.

The orientation of the house also proved to have a great effect on the energy rating. One of the designs was assessed multiple times, each time facing in a different direction – north, south, east and west. It was found that when oriented in an optimal direction, the house was able to achieve the 6 Star target with no double glazing. When this same house was oriented in a less optimal position, double glazing was needed throughout the whole house in order to reach the target.

Findings also proved that with good orientation, generally the additional cost of building a 6 Star mud brick house was not unreasonable. Just as importantly, this goal could be achieved without compromising on the design features which make mud brick homes so unique.

The study was seen to be a success, as it found that a typical mud brick house could in fact achieve a 6 Star energy rating by employing a range of techniques, despite earlier misconceptions. The NMA are intending to publish a hand book which will use the findings of this study to assist mud brick house designers, builders and home owners meet the mandatory 6 Star rating. The NMA hope to make this hand book available to its members later this year.