Buildings are our most important store of social and economic wealth. Cities are rich in wonder and beauty and a crowning achievement of humankind. However, their development and operation is the largest driver of climate change and resource consumption. Green buildings should reduce their emissions and resource intensity by a factor of four – bringing them into line with the aims of the Paris Agreement.
By 2030, an additional billion people will be living in cities which will drive demand for more than 150 billion meters of new building with an associated embodied carbon footprint of over 347 billion TCO2. The current trend is “carbon neutral” buildings, but as this only addresses the operating energy use carbon footprint – it leaves the ninety pound gorilla in the room.
The carbon intensity of materials can be up to fifty times bigger than annual energy use emissions, building type dependent. In Australia, the average life span of commercial buildings is barely twenty years and housing 40 years so a single focus on operating energy footprint cannot deliver the necessary total footprint reduction we need, as shown in Figure 1.
Relationship of Embodied to Operating Carbon Footprint
Reducing materials intensity delivers absolute carbon savings, and is not dependant on behaviour, and often saves money. The challenge has been in understanding the impact and how to use design to achieve the most efficient reduction pathway.
Luckily, there are three options:
- Alternative design solutions
- Using recycled content
- Low carbon supply chain and procurement.
1. Alternative solutions
Making strategic decisions on key design arrangements has the potential to reduce footprint up to 30%. Figure 2 shows a selection of structural systems. It can be seen that using a post tensioned structure over conventional concrete can deliver 40% less carbon per square meter. Structure accounts for 15-30% of the total embodied carbon footprint of a building.
Embodied carbon footprint of structural system alternatives
Another simple example is to consider epoxy or vinyl floor materials over vitrified tiling to achieve a resilient, water proof finish as shown in Figure 3. Making this strategic design decision can reduce your flooring footprint by over 60%.
Embodied carbon footprint of flooring alternatives
2. Recycled content
The use of high fly-ash content concrete, recycled fibre carpets and particle board is becoming more widespread. Nominating or selecting products with a high recycled content, can contribute to a lower carbon footprint. Figure 2 shows that adopting a high recycled content for post tensioned structures has the potential to reduce carbon content by 30% over virgin approaches.
3. Low carbon supply chain
Nominating or specifying low carbon supply chain sources for key materials such as aluminium, copper, steel, glass and brick is key strategic decision. Brickworks for example have launched a Carbon Neutral Brick. Using this brick over regular brick has the potential to reduce the footprint of cavity brick walls by 50%.
Bringing it Together
Most designers we know are motivated to deliver the most responsible design they can but just lack access to information on these three strategies and certainly don’t have time to do their own research.
Luckily, that is our mission. The Footprint Company have compiled this knowledge into The GreenBook™ which is a visually engaging, standards based guide to low carbon design solutions. The GreenBook™ provides designs with access to the carbon footprint of over 1,000 materials and design assemblies as well as key element benchmarks and visual design pallets.
Gain the jump on your peers and deliver eco-design excellence for your Clients. Download the free trial today.