Sustainable Workspaces, County Hall, London

Sustainable Workspaces is the redevelopment of a part of County Hall – a Grade II* listed building and the location of the former Greater London Council (GLC) – which was left unused since the abolishment of the GLC in the 1980s. The project was completed using a JCT Design and Build Contract.

Sustainable Workspaces is a branch of project client, Sustainable Ventures, a business that works with sustainable start-ups to provide investment, community, innovation and workspace. Having outgrown their previous location, they acquired a 3,600m2 space within part of the fifth floor of the former Greater London Council Building. On the surface, the brief was to retrofit the space to provide a vibrant and affordable workspace, including the creation of private offices, event spaces, innovation labs, cafes, and breakout areas. At the core of the project, however, is to achieve this with an absolute commitment to a low-impact design philosophy, focusing on minimizing embodied energy, reusing existing materials and fabric wherever possible, adding new elements from waste sources, and keeping repair and alterations to a minimum.

During the design phase, the architect, Material Works, used carbon calculation software to assess the impact of the design against what would be a typical ‘benchmark’ office fit-out. What they discovered was that reducing the scope and expectation of the finish, for instance omitting the usual layers of suspended ceilings, raised floors, plastered and painted surfaces, and so on, made a significant difference. This led to a rethink of what a retrofit might look and feel like, moving away from reinvention, and celebrating a less polished version of what is already there.

As such, the project reuses and retains as much of the existing fabric, fittings, and fixtures as possible. Where new elements have been added, their focus is on full life-cycle considerations. Materials are chosen for their low carbon and limited post-life impact, with an emphasis on being highly renewable or with significant waste and recyclable content.

One example is the space’s modular partition wall system, developed by U-Build. The plywood design is demountable and has minimal mechanical fittings which can be easily reconfigured.  A large amount of the wall system was sourced from Sustainable Workspace’s previous location and reused. Other joinery items are also developed in a modular way with clearly visible fixings or limited adhesive that allows for easy configuration, disassembly, and reinstallation. Finishes for the joinery are created from waste coffee and vegetables.

Other elements are built from waste materials, natural plant forms, and even unwanted industrial byproducts – composite boards formed from agricultural waste, cork flooring, mycelium acoustic baffles, and a countertop formed from reclaimed building rubble.

Light fittings formed from recycled single-use paper coffee cups were supplied by specialists, Blast Studio.

Existing doors, windows, flooring, and plaster have been retained, and much of the furniture has been sourced from reclaimed supplies. Fabric repairs have been limited to the essential, and redecoration has only been applied in those areas of high footfall and expected wear – revealing the layers of previous finishes, as well as the scars left by previous alterations.

This challenging project has been achieved not only in the context of its innovative commitment to a sustainable approach, but also with a limited budget, and within a century-old building in a serious state of disrepair. For every action, the design team had to consider the practical and aesthetic value against the financial and environmental costs – deciding carefully if each feature was genuinely required, looking at how it would be made or sourced with minimal impact, and what will happen at the end of its current use. The result is a project with 1,150 tonnes less embodied carbon than what would be generated through a typical office fit-out project.

The JCT Design and Build Contract is used on a wide variety of construction projects, and especially where there are complex and specialist requirements. JCT contracts have been at the forefront of enabling sustainable working, but this goes even further with the launch of the JCT 2024 Edition, where the previously supplemental provisions relating to Sustainable Development and Environmental Considerations, have been made mandatory within the main contract.


Project data

Start: October 2022
Completion: April 2023
Gross internal floor area: 3,686m2
Contract: JCT Design and Build Contract 2016
Construction cost: £4.25m
Architect: Material Works Architecture
Client: Sustainable Workspaces C.I.C.
Main contractor: Cast Interiors
M&E consultant: Taylor Project Services
Project manager and QS: Quartz Project Services
Modular wall design: U-Build
Services engineer: Taylor Project Services
Mycelium and waste stream finishes: Biohm
Principal designer: Material Works Architecture
Principal contractor: Cast Interiors
Approved building inspector: JM Partnership


Environmental performance data

Percentage of floor area with daylight factor >2%: 70%
Percentage of floor area with daylight factor >5%: 40%
On-site energy generation: None
Annual mains water consumption: 20 l/person/day, 5m3/person/yr (estimated)
Airtightness at 50Pa: Unknown
Heating and hot water load: 19.13 KWh/m2/yr (calculated by DSM modelling)
Overall area-weighted U-value 2.5 W/m2K: (excluding floor, existing building)
Design life: 15-20 years
Embodied / whole-life carbon: 48.05 kgCO2eq/m2 (excluding MEP)
Annual CO2 emissions: 6.21 kgCO2eq/m2 (calculated by DSM modelling)