Sustainability Report

Sustainability information provided by TP Bennett with additional information sourced from Arup and Wates Group.

Embodied carbon overview

• A fabric-first approach was combined with careful consideration of the structure, materials, and construction process. The steel frame and composite concrete deck were selected to provide large, flexible floorplates while reducing both the number of foundations required and the quantity of concrete used.
• The large-span steel frame reduces the need for concrete columns and limits the number of piles. Cellular beams reduce the weight of the structure, allowing shallower foundations. Off-site manufacturing of the frame also reduced carbon during construction.
• Embodied carbon was reviewed continuously during the design process, with workshops held at every RIBA stage to identify opportunities for improvement. Later assessments reported embodied carbon of 881 kgCO₂e/m² and upfront carbon of 533 kgCO₂e/m².
• Material choices were scrutinised through TP Bennett's Responsible Sourcing Questionnaire. Suppliers and manufacturers were asked to demonstrate responsible sourcing and evidence of recognised sustainability credentials, including EPDs, BES 6001, and ISO 14001. This informed the specification of a number of interior finishes, including low-carbon and carbon-neutral products where appropriate.
• Internal finishes were specified to be robust and hard-wearing, with consideration given to reducing material waste. Interior layouts and material set-outs were carefully coordinated to minimise offcuts and waste, while the use of recycled raised access flooring was also explored.
• During construction, waste was monitored through Qflow, allowing material use and waste streams to be tracked and incorporated into the project's carbon assessment.

Bibliography

Arup (n.d.) Setting a new standard for sustainable office development. Available at: https://www.arup.com/projects/11-and-12-wellington-place/ (Accessed: 12 August 2026).

Wates Group (n.d.) 11 and 12 Wellington Place, Leeds. Available at: https://www.wates.co.uk/projects/construction/commercial/11-12-wellington-place/ (Accessed: 12 August 2026).

• Ambitious airtightness and U-value targets were established with the client from the outset. During the project, the sustainability ambitions continued to evolve, in part due to the pause created by Covid, which provided an opportunity to reassess the brief. The client recognised that occupier expectations for office buildings were changing and that future occupiers would increasingly demand high-performing workplaces.
• The revised targets included BREEAM Outstanding, EPC A, and a five-star NABERS Design Reviewed Target Rating. These ambitions influenced the design, including an upgrade of the facades to triple glazing, refinement of the detailing to maximise airtightness, and the introduction of rooftop photovoltaics.
• The bronze-coloured facades of 11 & 12 Wellington Place incorporate two triple-glazed Schüco curtain wall systems. The main facades use the Schüco FWS 60 system, while the glazed link is formed from a Schüco AF UDC 80 SG unitised curtain wall system. Saint-Gobain COOL-LITE XTREME solar-control coatings were specified across the external glazing to reduce solar gain, while the light-coloured projecting bronze fins provide passive shading and help improve comfort within the office floors.
• Particular attention was also paid to thermal bridging, including the detailing of the inset balconies, where high-performance insulation was used to maintain the performance of the building envelope. The resulting airtightness figure of 1.47 m³/hr/m² at 50 Pa significantly exceeded expectations.
• Fundamental changes were also made to the building services. An all-electric reversible air-source heat pump system replaced gas-fired boilers and air-cooled chillers, eliminating fossil-fuel use from the building services. High-efficiency ventilation, improvements to lighting efficiency, and enhanced controls were also incorporated.
• Roof-mounted photovoltaic panels contribute on-site renewable electricity generation. During the project, the PV installation was increased from 500 to 700 square metres, enabling 11 & 12 Wellington Place to operate entirely on electricity supplied through a combination of on-site generation and a renewable energy tariff. This meets the requirements of the UKGBC net zero carbon operational energy standard.
• At design stage, 11 & 12 Wellington Place targeted operational energy use of no more than 43 kWh/m² per year (NLA), representing 41 percent less energy than the average UK office building.
• A dedicated real-time energy-management and metering system provides continual feedback on operational energy use through the smart building platform. The platform also gives tenants control over functions including lighting and temperature.
• The commitment to NABERS embeds a long-term sustainability strategy into the operation of the development. The buildings have since achieved a 5.5 Star NABERS UK Energy Rating, placing them among a very small number of UK offices to reach this level of measured operational energy performance. Tenants are required to uphold certain standards in use for the buildings to continue performing as intended.

• Durability informed a number of material choices. The facades are predominantly formed from aluminium curtain walling, triple glazing, and mechanically fixed components selected for longevity and ease of maintenance. The repetitive nature of the facade detailing supports build quality and long-term performance.
• The roof incorporates an IKO inverted roof system, selected for its durability and to protect the waterproofing membrane over the lifespan of the buildings, extending its service life.
• The development has a design life of 60 years and is supported by maintenance strategies intended to help the buildings continue performing as originally designed.