This 12-storey office building is one of three Make projects at New Bailey, a vibrant mixed-use regeneration masterplan in Salford, Greater Manchester.
Eden is a LETI Pioneer project, designed to achieve net zero operational carbon and champion sustainability, resource efficiency and wellbeing at every level. Delivered for English Cities Fund (a joint venture between Muse, Legal & General and Homes England), Eden dramatically enhances the biodiversity of the masterplan with its 3,300m² living wall, introducing a major piece of green infrastructure on the site of a former surface car park.
Beneath its verdant facade, the building has been continuously refined to improve building performance wherever possible – from using reclaimed and natural materials through to reducing the weight of the lift cars to reduce operational energy. These efforts have resulted in Eden being the first new build commercial project in the UK to achieve a 5.5-star National Australian Building Rating System UK Design Reviewed Target Rating (the maximum possible rating is 6 stars, which hasn’t yet been achieved in the UK).
Internally, a double-height ground floor reception space welcomes both building tenants and visitors. The ground floor also includes end-of-trip facilities which exceed BREEAM ‘Outstanding’ guidance, including over 150 cycle spaces and 13 showers. A roof terrace provides outdoor space with views across the River Irwell.
Eden’s most distinctive feature is its living wall, which covers 3,300m2 of the facade – every elevation from level 1 to 11, only excluding the side core – with 32 species of evergreen and perennial plants. The idea was born during the 2020 Covid-19 lockdowns, when we were all craving closer connections with nature. Now just three years on, the living wall has come to life, but its advantages extend far beyond aesthetics. The wall significantly boosts biodiversity for the entire masterplan, absorbs air pollution, reduces urban temperatures and refreshes the area’s identity, creating an architectural marker in Salford. The plants can be seen from inside the building on the office floorplates, giving workers visual connections to nature from their desks. This biophilic element of the design is just one way we’ve embraced the WELL Building Standard principles, which aim to improve human health and wellbeing through design.
Designed in collaboration with green wall specialists Viritopia (formerly ANS Global), the living wall’s 350,000 plants were grown at Viritopia’s nursery in Chichester, West Sussex. From young plugs – some as small as a thumbnail – the plants were cultivated at the nursery and given time to mature before being installed onto the building in cassettes. As the plants grow and bloom across the seasons, the appearance of the building will change with them.
To maintain the health of the living wall year-round, we coordinated the design of a watering system that uses recycled rainwater from the roof. Irrigation occurs on a daily basis via concealed vertical and horizontal pipes that feed the plant cassettes. The amount of water used will be monitored and adjusted remotely in response to local weather and the health of the plants. We’ve also enabled the system to switch over to mains water supply if necessary. This system ensures the plants remain healthy throughout the year, and if there are any species that are struggling to survive, they can be easily replaced without impacting the overall appearance and structure of the wall.
Eden is one of a handful of LETI Pioneer projects and has been designed in line with the UK Green Building Council Net Zero Carbon Buildings Framework definition to achieve net zero carbon in operation. The structure beneath the living wall is crucial to this. The 500mm depth of the facade and backing wall provides thermal benefits, reducing heat loss and the need for air conditioning while improving comfort levels on the office floorplates. The backing wall of the facade also helps Eden achieve a 0.15W/m2K U value, a 0.30 G value, and a low fabric permeability rate – benchmarks typically associated with Passivhaus standards.
While the facade goes a long way to reduce operational energy, our building management system (BMS) infrastructure provides building users with collective agency to control their environment. The BMS allows tenants to install continuous monitoring systems for energy use and indoor environmental quality as part of their office fit-out, employing integrated sensors that monitor CO2 levels to maintain good air quality. Our MEP ventilation strategy exceeds BCO guidance on fresh air rates, which in turn ensures tenants work in a healthy and pleasant environment. Looking ahead, we’re aiming for the 5.5-star NABERS Energy Rating to be applied to the building once the in-use data is available (12 months after completion), and ‘green lease’ agreements are in place to ensure tenants are aligned with the net zero operational carbon vision for the building.
Maximising the green wall’s coverage has various benefits, such as reducing solar gains and improving air quality, but we needed to carefully consider how it would impact fire safety. Working alongside fire engineers OFR to understand key guidance documents – including AD B, BS EN 13501-1, and the UK government’s Fire Performance of Green Roofs and Walls report – we identified the site’s constraints and opportunities. Given the building height of 49m, distances to the site boundary, and the 60:40 ratio of solid to glazing, our external surfaces needed to meet a fire classification of B-s3-d2 or better. The Viritopia modular living wall system that we used has been tested to comply with BS EN 13501-1, exceeding the brief and achieving a classification of B-s2-d0.
“Our intent was to push the client’s net zero operational carbon requirements as far as possible, which required undertaking a holistic approach to design from early-stage work and having that as a common thread throughout the design and construction phases.”
Stuart Fraser, lead architect, Make
There’s no silver bullet when it comes to sustainable design. From the macro to the micro, countless decisions across the design and construction of Eden helped us reduce operational and embodied carbon and boost health and wellbeing. Working closely with sustainability consultants Cundall and our client ECF, we conducted over 20 studies to determine the most efficient building, balancing architectural, structural, MEP, environmental and financial factors.
Starting with the massing, we pushed the core to the side of the building to create large, open-plan floorplates. This move fills the floorplates with natural light while providing panoramic views and flexibility, allowing the floorplates to be split for dual-tenancy configurations if needed. Based on solar studies, we incrementally increased the window sizes along the east and north elevations to maximise views while minimising solar gains. Another key move was our decision to omit a basement and instead split the plant across the roof and the mezzanine level – a choice which dramatically reduced embodied carbon.
Our utilitarian approach to the internal finishes further reduced embodied carbon. We left soffits and services exposed, as well as most of the concrete surfaces in the core, only applying finishes where absolutely necessary. This had the dual-advantage of saving waste while being financially beneficial, as we weren’t overspending on materials and installation or adding finishes which might later be removed during tenant fit-outs. Using circular economy principles, we integrated recycled materials throughout the building: the office levels feature recycled raised access floors, and the lobby and circulation areas utilise recycled sports flooring from the University of Central Lancashire. These decisions all added up to reduce our upfront embodied carbon intensity to below 700kgCO2/m2, compared with over 1,000kgCO2/m2 for a typical development of this type.
To improve operational efficiency, we incorporated enhanced ventilation, which exceeds the latest BCO standards, plus high-efficiency air source heat pumps that generate low-carbon heating, hot water and cooling. By specifying lightweight material finishes for the lift cars, we were able to reduce their weight and in turn lower the amount of energy needed to operate them. These small wins helped us achieve the 5.5-star NABERS UK Design Reviewed Target Rating and ultimately meet ECF’s brief: to design the most sustainable building possible within the budget and site constraints.
