Reduce, Reuse and Recycle
Energy efficient lighting, solar panels, ceiling fans and energy star appliances are some of the many “sustainable” choices that play a part in reducing greenhouse gas emissions (GHG) emissions. Given that the building sector contributes to around 40 per cent of all GHG emissions, these products (and others like them) are all valuable in helping to reduce the operational energy of a building. Operational energy of a building refers to the energy that is used for heating, cooling, lighting, running equipment and appliances etc) once a building is occupied.
While the construction industry is getting better at reducing emissions from operational energy, there is another source that needs to be considered; GHG emissions from embodied carbon.
What is ‘embodied carbon’?
“Embodied carbon consists of all the GHG emissions associated with building construction, including those that arise from extracting, transporting, manufacturing, and installing building materials on site, as well as the operational and end-of-life emissions associated with those materials.
The traditional starting point for many in the construction industry has been to remove old buildings and structures, clear the site and build new.
However, as our understanding, and ability to measure, embodied carbon increases, it is becoming apparent that the environmental movement’s mantra, Reduce/Reuse/Recycle, can be equally applied to the construction industry and the adaptation of buildings and the contributing construction materials.
Reduce (refuse) | Unnecessary new construction
The first step in a sustainable design process should be to consider whether it is possible to reuse or repurpose an existing building. Indeed, the very first question that should be asked – is new construction truly necessary for the project? Can the existing building be adapted to meet the needs of the homeowner or business thereby reducing the need for new construction?
Whilst this may not initially be the easiest approach, prolonging the useful lifetime of an existing building by reusing it can potentially save material costs, and lessen the embodied energy impacts of a new build.
Reuse | Long term adaptability
Because of the long lifetime of buildings, it can be very difficult to anticipate the possible future uses of a building at the time of design. However, recognising the possibility of future repurposing of a building, architects can design with a level of flexibility in mind to support long-term sustainability. Looking at how a building is utilised and how a building may be later be adapted as use changes are important design decisions. A building designed for adaptability is ultimately more sustainable in the long term.
Recycling | Materials Choices
Whether a building is being reused or being demolished, it is important to look at opportunities for reusing and/or recycling construction materials rather than have the construction waste get sent to landfill.
Many construction materials are already able to be either reused or recycled. Concrete can be crushed down to create concrete aggregate; steel and glass can also be recycled. Salvaged timber can be utilised in numerous ways. Clay bricks and roof tiles can be used as aggregates. Aluminium as well as paper and carboard are also able to be recycled.
The circular economy
By and large, today’s manufacturing takes raw materials from the environment and turns them into new products, which are then discarded into the environment. It’s a linear process with a beginning and an end. In this system, limited raw materials eventually run out. Waste accumulates, either incurring expenses related to disposal or else pollution. Additionally, manufacturing processes are often themselves inefficient, leading to further waste of natural resources. In a circular economy, however, materials for new products come from old products. As much as possible, everything is reused, re-manufactured or, as a last resort, recycled back into a raw material or used as a source of energy.
https://www.unido.org/our-focus-cross-cutting-services/circular-economy
