Green Star Homes unpacked: how to put the right roof over your head

30 Nov 2022

Selecting a roof for your new or renovated home goes beyond colour choices and materials. Getting it right can impact how comfortable your home will be season-to season and how it responds to Australia’s weather patterns - it’s a decision that could even lower your energy bills. We recently spoke to Laura Guccione, Senior Sustainability Technical Advisor at BlueScope, about how COLORBOND® steel can help boost the resilience of our homes, and help protect our most important and expensive asset.

COLORBOND® steel is an iconic Australian brand that’s built into homes around the country. For over 50 years it has provided products and colours for the roofs over our heads – from the coast to the hinterlands and through to the outback.

Our climate is changing rapidly, and the resilience of our homes is being tested like never before with extreme heat, bushfires and high winds. We need homes that can withstand these changes, keep us comfortable all year round and provide energy efficiency to keep the cost of living and carbon emissions down.

Laura says we can start by considering the colour of our roof, “Roofs are in direct sunlight for a big part of the day, if the roof is dark it can absorb heat and make the home beneath hotter, whereas lighter colours are better at reflecting or bouncing heat back into space, which can help the whole building stay cooler,” explained Laura.

BlueScope’s own research found that during hot sunny weather, the surface temperature of a light-coloured roof can be up to 35°C cooler than a dark-coloured roof.  While it is widely known that lighter colours are better at reflecting heat, COLORBOND® steel’s Thermatech® technology, which is designed to reflect more of the sun's heat on hot sunny days, can help even darker colours [in the COLORBOND® steel range] have solar reflective properties which may help a building stay cooler. 

Laura Guccione, Senior Sustainability Technical Advisor, Bluescope

“We’re seeing more interest from consumers regarding lighter or paler coloured roofs as a way of improving their thermal comfort, and we’ve recently added two new paler colours to our range to provide greater choice.

“More developers - who may be anticipating building code changes – are contacting us too, and we take regular enquiries from architects and designers, as well as project teams looking to use lighter colours for roofing that could help them achieve the Green Star Heat Resilience credit (found in Green Star Buildings and Green Star Homes),” shared Laura.

Combining COLORBOND® steel with appropriate insulation can help buildings maintain greater thermal comfort all year round. When our homes are thermally comfortable – for example, naturally cooler in summer – we're less likely to switch on cooling appliances which is an immediate saving. Roofing made from light colours can be used to help create cool roofs, which can help reduce the intensity of urban heat islands.

UNSW research found if the whole of Sydney implemented cool roofs, energy consumption for cooling residential and commercial buildings would decrease by up to 40 per cent in total. It also found that the benefits are potentially lifesaving and can reduce heat-related mortality by up to 30 per cent.

COLORBOND® steel undergoes extensive testing, which is critical when the resilience of Australian homes is being put to the test like never before.

“At our NATA (National Association of Testing Authorities) certified lab in Port Kembla we include testing for corrosion and paint performance (among other things),” explained Laura. 

"But the only way to truly test material is by putting it out in the elements so we place samples at highly exposed sites near Wollongong NSW and Rockhampton QLD and leave it for years (indeed decades) to test different facets of performance such as colour durability and corrosion resistance. 

“We also check performance and durability during cyclones, hail and bushfires. This real life testing in some of Australia’s harshest conditions, assists us to continually develop COLORBOND® steel particularly in relation to its durability and aesthetics,” said Laura.

COLORBOND® steel also won’t burn or catch fire so it can be a key part of bushfire design solutions. If you’re one of many Australians living in a bushfire prone area, the CSIRO found that when used as boundary fencing, COLORBOND® steel can offer greater protection than other materials. 

Evidence also shows that hailstorms are likely to increase, especially in Australia’s south-east which is currently inundated with floods and bouts of high winds. Laura says that generally, COLORBOND® steel roofing is robust in the face of hail stones, “The roof sheeting of our products absorbs the energy of the hail stones and, while indentations may occur along with the loss of the paint topcoat, the product typically remains structurally sound.”

COLORBOND® steel’s durability and long life means homeowners need to replace it less often, but its environmental credentials go beyond resilience. BlueScope is embracing the circular model to address the problem of embodied carbon and it has published climate commitments and a decarbonisation pathway. BlueScope is also a founding member of ResponsibleSteel™ - the global steel industry's first sustainability standard and certification program – and achieved Site Certification for its Port Kembla Steelworks in early 2022.

Green Building Council of Australia thanks BlueScope, a Future Homes supporting partner, for their ongoing leadership and their support of our activities in this space. Green Star Homes is on the forefront of homes that are healthy, positive and ready to respond to our changing climate. Keen to know more? Visit our Green Star Homes resource.