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Sustainable leadership

Showcasing projects that championed sustainable techniques, retained existing structures, embraced the circular economy and benefited society.

We hope you enjoy reading about all the inspiring projects on this page. If you click or tap on an image, you can read about a project in more detail.
As part of our online celebration, we asked the public to vote for their favourite projects. We are delighted to announce that the winner of the public vote in this theme was Hobhouse.


2020 Winning project : Hobhouse

Location : London, UK
Submitted by : Thornton Tomasetti

A mixture of new and old technologies are used to create an expressive and efficient building. The building was sensitively constructed within and on top of John Nash’s existing masonry structures. By working collaboratively with the architect and English Heritage, it was possible to minimise structural intervention. The historic fabric of the vaults and the retained building were also preserved.

Visit winner's website
The inside of a partially constructed building. Glass and metal feature heavily.

1 Finsbury Avenue

Location : London, UK
Submitted by : Arup

A 250,000sq.ft state-of-the-art office development inside a now Grade II listed building. A strategic decision to retain the existing building avoided the need for demolition and rebuild. This and detailed engineering design saved approximately 12,000 tonnes of embodied carbon.

An old building with green doors and window frames.

33 & 34 Trumpington Street

Location : Cambridge, UK
Submitted by : Wright Consulting Limited

A mixed-use development created through the conservation, repair and conversion of two partially derelict Grade II listed timber framed properties. A detailed understanding of piecemeal historical developments to the site was key. It meant that repairs respected and maintained the original load paths and structural form. It also allowed for new M&E services and energy efficiency improvements.

A large hall with suspended ceiling lights. People sit at tables in the hall.

Bath School of Art & Design - former Herman Miller Factory

Location : Bath, UK
Submitted by : Mann Williams

A project to transform and adapt a Grade II listed building. Completed in 1977, the factory building won awards for its innovative approach to flexible architecture. Although listed, the success of the original design allowed the building to transformed. This project is an exemplar of sustainable design. It embraces the circular economy while also securing the protection of our built heritage.

The inside of a library. Children sit reading books.

Billie Jean King Main Library

Location : California, USA
Submitted by : Skidmore, Owings & Merrill

A resourceful design that led to a 65% reduction in concrete waste. The library’s superstructure is composed of wood, steel and concrete. Each material is strategically employed throughout the structure to take advantage of its respective properties. Connections were carefully detailed to enable a seamless transition between the different materials.

<h4><b>Brunel Building</b></h4>

Brunel Building

Location : London, UK
Submitted by : Arup

An external structure that allows for big, adaptable and column-free internal spaces. Rigorous structural engineering and collaboration helped meet the design intent of this workplace. It also led to several construction innovations. Sustainability was considered balancing the aim of a low-impact, optimised structure while allowing for flexibility during use. This helps minimise whole-life carbon.

A side view of a house. The ground floor has glass walls.

Dorset House

Location : Bristol, UK
Submitted by : Element Structures

A contemporary hybrid timber and steel frame house. It features a high thermal efficiency timber frame and PassiveHaus principles. The structure plays with the lightweight nature of the frame. A column-free glazed corner combines with slender columns. This is achieved with engineering diaphragm floors, timber racking walls and X braced steel frames.

A view down some railway tracks with overhead power lines.

Elizabeth Line OLE Gantry Rigorous Assessments

Location : South East England, UK
Submitted by : Buro Happold

A sophisticated piece of engineering analysis allowed the reuse of vast amounts of existing infrastructure. The new Elizabeth Line includes existing above ground sections installed with new overhead line equipment supported by gantries of up to 70 years old. Engineering analysis led to most of the existing structures being safely retained. This resulted in significant programme and cost savings.

A glass sided sky bar.

Guinness Storehouse Gravity Bar Extension

Location : Dublin, Ireland
Submitted by : Arup

A horizontal extension of an existing gravity bar above a historic, protected structure. Constructed in 1904, it was Ireland’s first mild steel building. The project followed the principles of minimal intervention and reversibility, reflecting best practice in the conversion of historical structures. The entire building was fully operational and open to visitors throughout construction.

A balcony running along the side of a building. The balcony has grass planted on it.

Hilton House

Location : Manchester, UK
Submitted by : WML Consulting

The refurbishment and extension of a 1960s structure. Balancing existing and proposed loads was key to this project. Heavier existing structure was removed in some areas. This allowed additional lightweight floorspace to be constructed without significant structural strengthening at lower levels. The result was the modern open-plan office specification being delivered with cost savings.

A view of the side of a building. The window frames stand out from the building.


Location : London, UK
Submitted by : Thornton Tomasetti

A mixture of new and old technologies are used to create an expressive and efficient building. The building was sensitively constructed within and on top of John Nash’s existing masonry structures. By working collaboratively with the architect and English Heritage, it was possible to minimise structural intervention. The historic fabric of the vaults and the retained building were also preserved.

<h4><B>King’s Scholars Pond Sewer Rehabilitation</B></h4>

King’s Scholars Pond Sewer Rehabilitation

Location : London, UK
Submitted by : Transport for London

A project to rehabilitate the 170-year-old Bazelgette sewer without the need for rail or road closures. The project boasts impressive savings of £23m and 26,443 tCo2 against the client’s original business plan. With a design life of 120 years, it eliminated catastrophic failure of the asset and associated disruptions and risk to the public.


A very large open plan work space with wooden roof beams. The internal walls are white.

National Automotive Innovation Centre

Location : Warwick, UK
Submitted by : Arup

An expression of harmonious and sustainable engineering design. An exposed lamella inspired timber Glulam and CLT roof unifies all the building’s spaces. The timber significantly reduces the structures carbon footprint. An upper storey design studio for clay vehicles required the suspended slab to measure live load movements in microns.

A view of an atrium roof looking straight up from the ground.

Republic Masterplan

Location : London, UK
Submitted by : Heyne Tillett Steel

A project that champions using engineered timber in large-scale developments to create efficient and sustainable structures. Republic has revitalised a tired 1990s office masterplan to produce a high-quality, low-carbon workplace and public realm. The new lightweight structures use engineered timber to increase and extend the lettable floor area without additional work to the foundations.

The interior of a large exhibition space.

The Silverstone Experience

Location : Northamptonshire, UK
Submitted by : Mann Williams

A restored and extended WW2 steel hangar housing a new museum. The existing structure was strengthened using a central support truss. This propped the roof and minimised site welding. Reusing the existing structure and minimising strengthening works helped to reduce the embodied carbon associated with construction. It also retained the original character of this historic structure.

A building constructed from glass, metal and wood. Foliage hangs from each floor.

The Spinningfields Pavilion

Location : Manchester, UK
Submitted by : Engenuiti

A highly innovative, four level structure formed of an externally expressed glulam and steel truss frame. This efficient timber-framed building is an example of sustainability best practice, sequestering the equivalent of 338 tonnes of CO2. The length of time required to grow the volume of timber used again in the Austrian forest is just 0.044 hours.

A modern building with a red lift on the outside.

The Standard

Location : London, UK
Submitted by : Heyne Tillett Steel

A former office building transformed into a contemporary hotel. Sustainability and low carbon design lie at the heart of this conversion. The project reuses the existing shell and adds three storeys. This delivers maximum site density and reduces the need for future demolition and redevelopment.

An internal view of a hall with wooden walls and a wooden roof.

Venue on the Green Youth Centre

Location : East Sussex, UK
Submitted by : Corbett & Tasker Ltd.

A low-cost hyperbolic paraboloid timber roof constructed with sustainably sourced timber. The need for an extensive temporary structure was eliminated using straight timber ribs acting as permanent formwork. The primary roof structure has been left exposed internally to honestly express the use of structural timber including the thin Kerto Hypar structural shell over the ribs.

A bridge crossing a river. The bridge is uplit.

Water Street Bridge

Location : London, UK
Submitted by : COWI

A 28m single leaf lifting bridge providing a road and pedestrian link. The bridge links Montgomery Square and Canary Wharf’s new district, Wood Wharf. The design overcame complex interfaces with existing assets and an active waterway, while pushing to reduce material volumes and energy use. A very ambitious construction sequence was skilfully carried out and brought the project to life.


A bright room constructed of wood and glass. There are a table and chairs in the middle of the room.

Wooden Roof

Location : London, UK
Submitted by : Webb Yates Engineers

A replacement of an existing lean-to conservatory in a Grade II listed building. The timber roof beams are fabricated with a saw-toothed ridge that creates facets in the glazing. This facilitates rainwater run-off to the drainage channels. To reduce the depth of the roof and maximise headroom, the timber is left exposed acting as both the structure and finish.


A large building with a sculpture on the side.

York House

Location : London, UK
Submitted by : Webb Yates Engineers

An eight-storey refurbishment and extension scheme providing flexible co-working space. The existing building was refurbished across all floors. Meeting rooms, open plan areas, reception, café, bike storage and changing facilities were all created. At the front, a new CLT extension was added. The existing structure was also extended at roof level with a cross-laminated timber (CLT) structure.


Image credits

Benny Chan Fotoworks, Billie Jean King Main Library; Hufton + Crow, National Automotive Innovation Centre; Ståle Eriksen, Wooden Roof; Agnese Sanvito, York House.