The Sutton Estate Regeneration, Chelsea

Innovative aspects of the housing design/building

The Deep Energy Retrofit (DER) involves four blocks with new lifts, ground floor apartments made wheelchair accessible, 81 one-to-four-bedroom flats, double glazed windows with aluminium frames and trickle vents, and re-opening closed balconies as private outdoor spaces for residents. A ground source heat pump acts as a collective heater via 200m deep piping in 25 boreholes distributing heat to each home through individual Kensa ‘shoeboxes’. The ventilation, heating, and thermal performance were designed together to allow each strategy to complement the other: insulation depth was limited, the ground source heat pump has a certain performance, and walls were made airtight.

The landscaping includes a new communal garden, natural stone hard landscaping, and soft landscaping that directs rainwater to the garden. A play trail will wind through the estate, transforming the spaces between building entrances into inviting, people-friendly areas. These will feature new trees, attractive landscaping, and enhanced facilities for bin and bike storage. The sunken garden has been updated and is a focal point for communal activity and respite. New cycle infrastructure also aims to encourage an increase in cycling as transportation. The estate office boasts a sedum roof and will be used by maintenance staff and whenever housing officers require offices on site.

Construction characteristics, materials and processes

The DER occurred while the four buildings were unoccupied. Floor plans were amended to accommodate new lifts and a greater household mix. The construction system adds the following to existing brick masonry walls: 50mm wood fibre internal insulation; 5mm reinforced lime plaster coat; double glazed windows with timber frames, aluminium fascia, and trickle vents. Where closed balconies existed, these were opened to provide some private outdoor space. Where they did not exist, prefabricated external metal balconies were fixed to the façade.

The maintenance regeneration was retrofitted with residents in situ with external façades designed to look identical to the DER. While it was preferable not to move, this was a challenge because residents have had to live with scaffolding for almost 2 years, impacting natural light and noise. During particularly disruptive periods or vulnerabilities, residents could temporarily move into vacant apartments on site. A phased approach was taken, largely block by block, where replacement of kitchens, bathrooms, boilers, and electrics occurred simultaneously on a property-by-property basis. This may mean more tenant disruption but minimises the duration of inconvenience to each home. Window replacements are being undertaken in conjunction with the external works to each block, including roof replacement, lightning conductors, pointing and brickworks repairs, and pest control measures. This maximises utilisation of the scaffold to the block, which represents a significant part of the costs, helping to achieve better value for money overall. Improvements were also made to the communal areas, door entry systems and lifts. The phasing of the 11 occupied blocks was developed to enable the scaffold to be removed in time for the landscaping works to be carried out.

Residents in all buildings were able to choose between materials and finishes: white or grey kitchen finishes, two different laminate workshops, and two vinyl floor choices. All bathrooms are finished in a white standard tile to ease maintenance. 

To meet Secure by Design (SBD) requirements front doors to each block will have a metal core and timber facades. Existing windowsills are at a height of 990mm. Bars at a height of 1,100mm are, therefore, added to the window internals to adhere to modern building regulations. The fence around the sunken garden will be replaced by a metal fence at a 1,100mm height.

Energy performance characteristics

The energy performance characteristics of the DER aim to improve energy performance from a baseline of 208 kWh/m²/year to the predicted results of 111 kWh/m²/year, a 38% reduction. The following measures have been taken to improve thermal performance: airtightness; 50mm wood fibre internal insulation; 5mm reinforced lime plaster coat; double glazed windows with timber frames, aluminium fascia, and trickle vents. A new ground source heat pump with individual ‘shoeboxes’ in each apartment facilitates low and constant heat through large, low service temperature radiators. After 6 years unoccupied, the DER buildings will become occupied in late 2024. Therefore, the actual improved performance is currently unknown.

The maintenance strategy improved energy performance through the following improvements: triple glazed windows with timber frames, aluminium fascia, and trickle vents; brickwork repairs to improve airtightness; adding loft insulation; and replacing boilers with new hybrid boilers.

Involvement of users and other stakeholders

The DER turned 159 flats, mostly studios and 1-2 bedrooms, into a mix of 81 one-to-four-bedroom flats accessible by lift. This new mix was chosen to meet the demographic needs of existing residents.

Residents are integral to the Sutton Estate. Clarion’s regular printed Sutton Estate newsletter, the ‘Chelsea Chat’ was distributed to all homes across the estate in the initial stages of the project and continued until 2021. All back issues are still available online. Through the pre-application design evolution process, two Design Update leaflets, plus a questionnaire, were produced to provide residents with the opportunity to engage. Six interactive events were held throughout the pre-application process, consisting of regular online residents’ workshop, a stakeholder walkabout and a public exhibition. A design steering group was generated from within the residents to discuss designs, gain feedback, and is now used to update on construction and share concerns. For example, there was concern over many households simultaneously cooking and showering at the same time, therefore the strategy was stress tested.

Communal events are also a key component to the estate’s philosophy. These include: a resident gardening club; monthly senior lunches; trips to the seaside, pantomime, and other estates; various training events, such as media and chairing meetings; and outdoor events in the sunken garden, such a fish and chip van. Apprenticeship schemes have been implemented for gardeners, adding further social value.

Relationship to Urban Environment

The Sutton Estate, Chelsea was funded by philanthropist William Richard Sutton, who bequeathed his fortune to the creation of The Sutton Model Dwellings Trust (now Clarion Housing Group) in 1900. Due to the industrial revolution and mass migration into inner cities, the working classes in the UK were living in extreme slum conditions. According to The Chelsea Society, “in 1902 a quarter of Chelsea’s community officially lived in poverty, and 14% [sic] lived in overcrowded accommodation”, bringing sanitation issues and the “potential of a health related pandemic”, to an otherwise affluent area. Sutton left instructions to set up a trust that would build and lease social housing for “use and occupation by the poor…[in] populous places in England” (Booth, 2015; SaveOurSutton, 2018). The Sutton Estate was built between 1912-1914 on a previously dense urban site. It was the third of four social housing estates erected in Chelsea by philanthropic institutions: (1) Peabody Trust Estate, Lawrence Street, 1870; (2) Guinness Trust Estate, Kings Road, 1891; (3) Sutton Dwellings Trust Estate, Cale Street, 1912-1914; (4) Samuel Lewis Trust Estate, Ixworth Place, 1915, directly opposite the Sutton Estate (Best, 2014). By the 21st century, however, the Sutton Estate dwellings had fallen into disrepair and in desperate need of refurbishment.

The Royal Borough of Kensington and Chelsea (RBKC) is now the second most expensive borough in the UK, after Westminster, and as such The Sutton Estate sits in prime real estate location. In 2018, the RBKC rejected a planning application, in part due to a resident orchestrated campaign “Save our Sutton”, which proposed to demolish the estate and rebuild, with part of the site sold for private ownership to fund new social housing. Plans to refurbish, retrofit, and regenerate began in 2019 and were accepted in 2021.

Two of the street-facing blocks rent their ground floor to commercial shops and cafés. The residents have been historically integrated into the wider neighbourhood through shared amenities such as laundrettes, and a Tenants Association that previously organised neighbourhood fêtes. With rising costs, however, replacing affordable services with new amenities, the integration of Sutton Estate residents within the wider neighbourhood is diminishing (personal communication, 2024).

The Sutton Estate responds to the following Sustainable Development Goals (SDGs):

Goal 3 Good Health and Well-being: All flats will be in safe and sanitary condition with healthy indoor air quality.

Goal 7 Affordable and clean energy: Passive and mechanical solutions to a reduction in energy costs and carbon output.

Goal 11 Sustainable Cities and Communities: estate remains 100% social housing and all residents can remain on the estate.

Goal 12 Responsible consumption and production: Energy consumption results are pending, but the expected energy reduction is 38% compared with pre-retrofit.