A solar reflective roof made using COLORBOND Coolmax steel from BlueScope Steel is helping to cool the stores at a new shopping centre near Lismore in northern New South Wales.

The use of BlueScope steel roofing with high solar reflectance properties has helped the Goonellabah Centre meet BCA energy efficiency requirements.

Housing a Woolworths store as the anchor tenant and 15 speciality stores, the Goonellabah Centre is clad with 5200m² of solar reflecting roofing made from COLORBOND Coolmax steel.

Architect Ian Pollard of Cottee Parker Architects said COLORBOND Coolmax roofing was chosen over the option of insulating the walls of the building.

He explained that the project had been in the pipeline for quite some time, during which there where changes to the BCA that meant they had to meet more stringent Deemed to Satisfy requirements, in which the energy efficiency of each part of the building is assessed in isolation rather than the building's performance as a whole. 

Mr Pollard said the project's tilt-up panel construction posed particular challenges in the context of the BCA requirements. Insulating the walls would have required them to add about 76mm of wall thickness, which would have taken away quite a bit of overall floor space while also adding to the building cost.

Cottee Parker Architects therefore decided to model the thermal performance of roofing using the BCA Section J Alternative Verification Method (part JV3), which allowed energy consumption simulation and the inclusion of trading one building element's performance with another.

By trading off the high efficiency of the COLORBOND Coolmax steel roof system, reductions were able to be made to wall insulation in other parts of the project. 

Walton Construction, the builder engaged specialist consultants to model the energy efficiency of the building and COLORBOND Coolmax steel in the colour Whitehaven was identified as having higher reflectivity than other materials. Their modelling found that COLORBOND Coolmax steel helped reduce the amount of heat penetrating the building, reducing the need for active air-conditioning and insulation to the building. 

COLORBOND Coolmax steel was able to assist overall thermal performance of the building while also meeting BCA requirements. 

BlueScope Steel's own studies show that an insulated roof made from COLORBOND Coolmax steel can lower the internal building temperature by up to 2°C compared to a roof made from ZINCALUME steel.