NEWS: How can the built environment industry prioritize the reduction of embodied carbon?

The reduction of embodied carbon in construction materials is as meaningful as reducing carbon in-use i.e.typically 40-70% of the total lifetime carbon cost in buildings is now its embodied carbon.

But not enough is being done to make the reduction of embodied carbon a priority in codes and regulations that govern the design and construction of the built environment. What should be done?

It’s time for regulations to prioritise lower embodied carbon materials in construction

The global pandemic we are living through is highlighting just how quickly the human race can mobilise to get things done when faced with an immediate threat. Vaccine development is progressing at an exceptional rate for a virus that has only been part of our lives for a matter of months.

But Covid-19 isn’t the only challenge affecting the human race that requires such urgent intervention. By the time the current health and economic difficulties have been consigned to the history books, there will be environmental consequences if we don’t equally prioritise climate change.

In construction and engineering, efforts to reduce carbon emissions will make a significant impact on helping to achieve net zero targets. There are many organisations already making major changes but with more than 40% of global carbon emissions resulting from the built environment, many others still need to follow, and quickly.

One key change should come from a broader acceptance that the reduction of embodied carbon in construction materials is as meaningful as reducing carbon in-use (typically 40-70% of the total lifetime carbon cost in buildings is now its embodied carbon). We need to ask why not enough is being done to make this reduction a priority in codes and regulations that govern the design and construction of the built environment. We should use our attained knowledge of embodied carbon to drive better decisions about the materials that are used in construction today.

Sustainability codes that were introduced just over a decade ago practically ignored embodied carbon in materials, so while these codes have had a positive impact in other areas of making our buildings energy efficient, they need updating.

What the industry desperately needs is to regulate embodied carbon, by measuring and setting limits on how much can be used. We would then see more businesses making a conscious switch to sustainable materials like low carbon cements and aggregates, in place of materials like Portland cement in its current carbon-intense form.

Furthermore, both planning policy and the property developer mindset should recognise that the most intuitive way to create a zero carbon building is to re-use the building that already exists.

The re-purposing and adaptation of structures is the most meaningful way of reducing embodied carbon. Over the last half century this debate has centred around conservation, and whilst conservation in its broadest definition remains highly relevant to sustaining our societies, the embodied carbon argument adds much weight to this decision-making process.

A policy driven change in mindset would also mean that timber – still often overlooked in the UK because of misperceptions around its properties – would become increasingly important.

A shift towards increased timber use is already happening in parts of the UK market, but it is a drop in the ocean. At Civic Engineers, we have recently worked on projects that have made extensive use of the material, such as the manufactured timber houses and an office building for developer, Citu (part of the Leeds Climate Innovation District), and a new timber-framed visitor centre at Delamere Forest in Cheshire. Indeed, calculating the embodied carbon of our structures has become as routine in our design process as structural analysis and element design.

But the industry shift isn’t happening quickly enough.

Currently the UK market for timber construction is still immature with too many misconceptions that are putting people off. On other projects where timber use would be wholly appropriate, we have seen higher costs and beliefs that timber immediately poses a fire hazard leading to its rejection in favour of more carbon-intense alternatives. We’ve also heard many stories about insurances and mortgages being refused for timber buildings.

In the aftermath of the Grenfell fire and the new restrictions on flammable materials, this caution is entirely understandable, but context is everything. Using timber as a primary structural material saves carbon emissions through the carbon captured and stored in the wood, and the avoidance of carbon-intense alternatives. It is incredibly versatile, which means it can be protected, and in some cases treated to perform safely under fire conditions whilst offering the strength/weight ratio to make it suitable for a surprisingly high number of purposes and capabilities. Most importantly of all, it can be replaced through managed plantations that ensure its long-term sustainability.

Increasing timber use is not a solution in itself, but better adoption of timber would mark a turning point in our industry’s efforts to use less raw material. Wider adoption can be driven by better education about the actual risks of timber, as well its benefits.

However, history has shown that real change only happens with regulations to back it up. That is how we’ve seen progress to date on climate change-related issues and it is what will persuade developers and constructors to overcome the existing obstacles in the UK market to better embrace lower carbon materials. For instance, Part L of the Building Regulations has evolved in the last decade to create buildings which are lower energy in-use. We now need to see other parts of the Building Regulations (such as Part A) changed to reduce embodied carbon in our buildings.

This year has shown us how pertinent global issues can be tackled swiftly when we have widespread collaboration and the collective will to make a change. It’s now our industry’s turn to play a part in helping to facilitate a change that has the power to impact all of us. We must use next year’s COP26 Climate Conference hosted in Glasgow, as an opportunity to accelerate this change.

This opinion piece was written for the New Civil Engineer by Julian Broster who is founding director at Civic Engineers