Reducing carbon reduces cost

The construction industry is constantly seeking innovative solutions to reduce its carbon footprint. One solution is adapting offsite techniques to address this challenge.

buildeco uses a cradle-to-site process that considers the total amount of embodied energy from extraction of the raw materials, through to manufacturing, transport and installation to occupancy. With one of the lowest carbon footprints in the industry, further carbon reductions of between 30-50% are achieved by buildeco’s lightweight structure requiring shallower foundations and fewer lorry deliveries.

Waste is further minimized by working with standardised components. Where possible, materials are sourced from suppliers at the required sizes, further reducing the carbon footprint.

buildeco buildings achieve low levels of captured carbon within the building due to the two main principal materials used in the structure.

Timber system

Timber is one of these, as it is the most ecologically responsible building material with 800 kg of stored carbon dioxide in each cubic metre. It is used for the construction of the cassette frame which is CNC machined from solid grade C24 timber or laminated veneer lumber (LVL).

For an example of C24 timber project (refer to Sectors tab and Modular Education Building ‘Classrooms’) and for LVL project (refer to Sectors tab and Modular Extensions ‘Modular Rear Extension’).

LVL is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. LVL offers several advantages over typical milled timber including cross laminated timber (CLT). It is stronger, straighter, uniform and less likely to warp, twist, bow, or shrink.

The other material used is magnesium oxide for the sheathing (known as MgO board). This is applied to both side of the cassette, forming the external skin for the composite panel. There is 400 kg of stored carbon dioxide in each 1000 kg of MgO board.

The manufacture of MgO board uses 50% less energy compared with the production of other cement-based boards. With the rising use of MgO board in the construction industry, it is being recognised for its environmental benefits. Magnesium is considered the eighth most abundant natural mineral with a plentiful supply expected to last for centuries.

Compared with similar-sized properties of 101 m², we estimate that a timber-frame house has 43 tonnes of carbon storage, and a traditionally-built house 25 tonnes, whereas a buildeco house has 85 tonnes, due to the greater use of the two principal materials in our construction methods.

Light gauge steel system (cold-formed)

Improved design solutions continue to be developed as buildeco strives to drive down costs. A new panel type manufactured from light gauge steel (LGS) has been developed to overcome the cold-bridging problems commonly found in steel frames. This new solution has been developed following enquiries from overseas requesting an alternative to the use of timber. Concerns were raised about possible termite attack on timber. The timber could be treated with insecticide but this is considered not to be environmentally-friendly. Light gauge steel panels will now be an optional choice for clients. The steel cassette frame will still have MgO sheathing boards applied to both sides, forming a composite panel.

For an example of LGS project (refer to Sectors tab and Modular Garden Retreat ‘Home Garden Room’) also (refer to Sectors tab and Modular Educational Buildings ‘Sure Start Nursery Centre’)

Steel circular economy

Sustainable economics reduces the burden on nature by ensuring that resources remain in use for as long as possible. Steel has been recycled repeatedly ever since it was first made creating new steel products. Steel is the most recycled material and maintains the inherent properties of the original steel. These properties can be modified during the steelmaking process to create many advanced steel grades.

Around 650 million tonnes (Mt) of steel are recycled around the world annually, avoiding over 900 Mt of carbon dioxide emissions. One tonne of recycled steel saves extracting 1,400 kg of iron ore, 740 kg of coal and 120 kg of limestone in raw materials; savings in electrical energy required to heat and produce the molten liquid; and savings in carbon dioxide emissions required for any transportation.