19 Cornwall Street is our first project which has achieved a 5-star design-reviewed target rating under the NABERS UK ‘Design for Performance’ process, and the only building in Birmingham to achieve a 5-star NABERS rating.
This highly sustainable, back-to-frame refurbishment by Willmott Dixon Interiors for Kier Property creates 139,000ft² of commercial office space and is designed to achieve net zero carbon by 2030.
Twenty-four electric vehicle charging points are provided among the 150 secure parking spaces. Openable refurbished windows and environmental sensors support occupant health and enable natural ventilation when appropriate.
Beyond its environmental credentials, 19 Cornwall Street delivers significant benefits to occupants and the wider community. The building features a multi-functional studio space, showers and changing rooms, an attractive communal roof terrace, and 74 cycle spaces with a cycle repair workstation.
What is NABERS?
NABERS (National Australian Built Environment Rating System) represents a fundamental shift in how we measure building performance. Unlike traditional certifications that focus on design intentions, NABERS rates buildings on their actual operational energy efficiency, requiring 12 months of real-world performance data. It's the difference between promising to be sustainable and proving it.
As our first NABERS UK scheme compliant building, 19 Cornwall Street has transformed an existing commercial building into the city's most sustainable office space, pioneering new approaches that align perfectly with our Now or Never strategy and setting a new benchmark for what's achievable in commercial property refurbishment.
How do you achieve a 5-star NABERS rating?
As one of only 34 buildings nationally registered under the NABERS Design for Performance scheme, 19 Cornwall Street demonstrates our commitment to delivering buildings with net zero operational carbon by 2030. Through efficient systems and 400m² of photovoltaic panels on the roof, the building is designed to generate as much energy as it uses. The project achieved an exceptional air-tightness test result of 3.8m³/m2.h@50Pa significantly better than the 10m³/ 2.h@50Pa minimum standard for new office buildings and exceeding the design stage target of 4.0m³/ 2.h@50Pa.
Tenants benefit from electrically driven VRF heating/cooling systems with individual floor digital controls, completely eliminating fossil fuel dependency. Smart technology allows them to track and adjust their energy usage in real-time, protecting them from future energy price rises while empowering them to meet their own sustainability commitments.
The building's predicted operational energy aligns with the UKGBC's interim target for net zero by 2050 and the emerging UK Net Zero Carbon Building Standard.
How was embodied carbon reduced at the design stage?
Driven by the environmental ambitions of Willmott Dixon's Now or Never strategy, the project team found innovative ways to reduce waste and embodied carbon throughout the build.
The project achieved LETI A++ for as-built upfront embodied carbon—the highest target achievable—and LETI A+ for whole life embodied carbon. All flooring was pre-used, with 3½ floors of raised access flooring reused from the building itself. While this approach didn't create cost savings due to glue removal requirements, it significantly reduced the project's embodied carbon footprint.
The use of a digital twin model enabled informed, energy-efficient decisions throughout the design process. Analyses revealed that retaining existing windows and not utilizing the atrium for cross-ventilation provided optimal outcomes, balancing energy efficiency, cost, and technical feasibility. This approach resulted in reduced capital costs, lower embodied carbon, and maximized lettable area.
The team also saved the customer £300,000 by simplifying the design for the partial infilling of the atrium, using the existing building's load rather than requiring new ground injections or piling.
What other accreditations were achieved at 19 Cornwall St?
The project's achievements have been recognised through other prestigious accreditations: BREEAM Excellent, WELL Standard Gold, and an EPC A rating. The award of a Wired Score Gold underlines the customer's smart building ambition.
Adam Worrall, deputy managing director at Willmott Dixon Interiors, said:
"We are passionate about creating sustainable, future-proofed workspaces, and 19 Cornwall Street is a great example of that.
"Kier Property shares our vision for energy efficient office design, and together we've transformed an existing building into a modern, high-quality space that meets the highest environmental sustainability standards."
19 Cornwall Street demonstrates Willmott Dixon's Now or Never strategy in action, combining sustainability and commercial success. It's not just Birmingham's most sustainable office building; it's a blueprint for the future of commercial property across the UK.
