Reducing embodied carbon begins in the design stages

Embodied carbon is the total emissions associated with the materials used to create a built asset– distinct from its operation. Comprising the CO2 emissions released during the extraction, manufacturing, transportation, and assembly of materials, depending on the boundary of an assessment, maintenance, replacement, deconstruction, disposal, and end-of-life aspects may also be included.  

While embodied carbon contributes to 11% of the worlds Green House Gas (GHG) emissions, operational carbon accounts for 28%; for this reason, traditionally embodied carbon has been commonly overlooked. However, a shift in focus may be on the horizon as recent estimates predict by 2050, levels of embodied carbon will match those of its counterparts.  

Embodied carbon is an often overlooked but critical component in the building lifecycle and must urgently be addressed. 

- Stephen Smith, Executive Director, Multiplex.

The road to sustainable building begins long before the construction phase, as the earlier embodied carbon is acknowledged, the more significant the impact a team can have on its reduction. Hence, consideration of embodied carbon during the initial design stages will continue to grow significantly. 

Specifiers working to reduce the carbon output of a project will play a crucial role in tackling the climate emergency. With essential design decisions made during the early stages of a project, architects have the power to navigate and integrate sustainable solutions and materials.

Design for durability 

One of the main methods used in reducing embodied carbon is the selection of resilient materials. This is because longer-lasting options require less maintenance and remove the need for frequent repair and replacement. Designs assembled with longevity benefit architects and clients alike as more durable materials reduce carbon emissions and decrease capital expenditure and post-installation costs. 

It’s about designing something really well… and we need to be designing for longevity and future deconstruction.

- Neil Pannel, Head of Design and Innovation at Property Solutions at Landsec.  

Efficient design 

Major advancements can be made in reducing embodied carbon by designing a building’s structure. Architects can considerably lower a project’s carbon footprint by measuring and reducing the use of default steel structures. Exemplifying the structural effect decisions can have, a case study of an 18-story building found that using a timber structure reduced embodied carbon by 26%.  

Effective space planning can streamline a building’s surface area and ensure only essential materials and products are used. Adding to this, using fewer finishes and instead incorporating structural materials can further save on emissions. Two sustainable examples specifiers are using are polished concrete floors and unfinished ceilings.  

To decrease embodied carbon across the entirety of a building lifecycle, architects should include effective passive design strategies in place of mechanical systems. This is because designs that take advantage of natural heating, cooling, and ventilation sources remove the necessity for active systems that produce higher levels of carbon emissions.  

Design for disassembly and re-use

Building materials and systems are projected to become increasingly more expensive. Therefore, disassembly design adds value to a project as clients can salvage, sell, or reuse building materials. Salvaged and second-hand materials make a huge saving on embodied carbon as the GHG emissions generated during their creation have already been produced and calculated. For instance, new steel has a carbon output five times greater than recycled steel.  Planned disassembly, re-use, and repurposing have the potential to cut emissions by up to 40%, saving on embodied carbon and money.  

How can architects influence embodied carbon levels throughout a project?

As the proportion of embodied carbon increases, architects must translate the importance of measuring CO2 emissions throughout the totality of their projects. An architect’s careful consideration and planning of low-carbon specifications could be lost if a contractor swaps out products or outsources from a location at a greater distance. To avoid this, architects should communicate their research and decisions making procedures with clients and contractors to ensure that embodied carbon is considered at each stage.  

The relative significance of embodied carbon will continue to grow as decarbonisation of the grid and operational emissions decline. Although several practices are yet to make the leap to measuring embodied carbon across their portfolios, several architects have started acting upon the mitigation and reduction opportunities found within the design phases of a project.