As construction faces increasing pressure to minimize its carbon output, the role of contractors in steering sustainability efforts is growing more pivotal. While carbon savings are often attributed to design decisions, the hands-on knowledge that contractors bring can shape a project's overall carbon performance in profound ways.

A critical success factor lies in involving contractors early on. When they're engaged throughout the entire project timeline—from planning to final delivery—contractors are better positioned to manage resources that contribute to emissions. Design teams may set the sustainability vision, but it’s often contractors who bring that vision to life through smart material choices, advanced technologies, and thoughtful buildability.

Back in 2021, Mace committed to eliminating 1,000,000 tonnes of carbon emissions from client operations by 2026. After surpassing that milestone by 2023, they raised their target to a bold 10 million tonnes. Drawing from experience on flagship projects, Mace has pinpointed five core areas where contractors can leave a lasting impact on both embodied and operational carbon.

1. Prioritizing Early Collaboration

The earlier contractors are brought into a project, the more influence they can have on sustainable outcomes.

One standout case is The Daubeny Project at The Oxford Science Park. “Early collaboration enabled us to re-engineer the foundation solution, delivering significant savings in carbon, cost, and programme duration.” The team shifted from a conventional piled foundation to a geostruct active raft design. This not only addressed challenging ground conditions and flood risks but also dramatically cut down the need for concrete and steel, achieving “a carbon dioxide equivalent (CO2e) reduction of approximately 3,000,000kg/C02e.” The achievement was made possible by close coordination with Subterra, the build contractor, before construction commenced.

2. Smarter Materials and Creative Construction

Reducing carbon starts with a simple idea: less building equals fewer emissions.

But turning that into reality demands more than choosing green materials—it involves rethinking construction itself. At Panorama St Paul’s, formerly the BT London HQ, more than 75% of the original structure is being preserved. “Cutting the carbon footprint in half and achieving carbon savings of 465 kgCO2/square metre” was made possible by swapping traditional concrete piles for a steel alternative, saving “296 tonnes of carbon.” Additionally, over 1,500 tonnes of Portland stone and granite from the façade were reused to further drive down embodied carbon.

3. Driving Innovation from the Ground Up

Contractors who influence methods and materials early can unlock significant carbon efficiencies.

Savvy clients are starting to see the benefit in this. At Heathrow Airport, Mace is testing artificial intelligence to optimize cement mixtures based on forecasted weather conditions. This reduces cement waste while retaining strength. Paired with “smart rock” sensors that track heat during curing, these tools “allow us to fine-tune material usage and reduce carbon without compromising program requirements – and in many cases improving it.”

4. Making Carbon a Business Priority

The familiar project priorities—cost, time, and quality—now have a fourth pillar: carbon.

Mace embraces this evolution in its work on the European Centre for Medium-Range Weather Forecasts (ECMWF), a Government Property Agency project. With a target embodied carbon of “500 kgCO2e/square metre at RIBA Stage 4,” it significantly undercuts the industry benchmark set by LETI for non-domestic buildings. “This has been designed from the ground up as a net-zero carbon development,” putting carbon on equal footing with financial and operational goals.

5. Monitoring Carbon in Real Time

Reducing carbon isn’t just about one-time decisions—it requires ongoing oversight.

Mace employs a dedicated reporting platform to monitor emissions throughout each project phase. “This tool provides data on carbon emissions, enabling us to identify areas for improvement and implement corrective actions promptly.” By continuously assessing performance and adjusting as needed, contractors help projects stay aligned with their sustainability commitments.

Looking Ahead

As the push for greener construction intensifies, contractors are in a unique position to make a difference. Whether it’s collaborating early, embracing innovative solutions, or embedding carbon considerations into every decision, their influence spans the entire construction journey.

By following these practices, contractors can not only meet today's demand for sustainable buildings—but also set the pace for a lower-carbon future across the industry.

Originally reported by Macegroup.