127 Kensington High Street

WSP worked with Ashby Capital and Janson Urban to reuse and grow the existing structure of the Kensington Building, which created larger more effective retail and office spaces while reducing carbon emissions from construction.

If you want to know why more buildings should be reused and repurposed, rather than demolished and built anew, take a look at 127 Kensington High Street. Our multidisciplinary engineering has helped transform a tired and bleak four-storey 1970s block into a six-storey mixed-use building providing next-generation office space and, through the creation of a new retail arcade, better connectivity to High Street Kensington Underground Station.

Location

London, United Kingdom

Project Status

Complete

Existing structure reused

>60%

Increase in overall gross area

~45%

Below current LETI embodied carbon target for structure

40%

Image on the left shows the parts of the building that were demolished in red and the image on the right shows the new structure in blue.

The benefits of reusing and repurposing an existing building are seen in the structural frame more than anywhere else. Reusing 60% of the existing building structure has made possible a larger development – of a size that planners and the local community would have been unlikely to support for a new building. (Adding two storeys and growing the north and west elevations has increased the overall gross area by 45%.) It has also achieved a level of embodied carbon for the building’s structure that, at 220kg per m², is 40% below the current LETI target and meets the levels required for buildings being designed in 2030. How did our structural engineers achieve this?

By removing the heavy concrete façade, finishes and other elements from the building and replacing them with lighter elements, we were, through a load balance analysis, able to build higher and bigger reusing the existing foundations. With only minimal additional strengthening required, there were large savings in cost, programme and carbon compared to either demolition and rebuild, or extensive strengthening. There was also much less construction noise, dust and disruption for the local community to put up with. And the complex interfaces with neighbours – including the operational underground station – were simplified.

The areas in blue show where we incorporated the new structure. The left image is of the foundations and shows where we retained the existing foundations. The right image shows the combination of new and existing structure of a typical floor area.

Reusing structures in this way doesn’t mean compromising on the finished product. The design team were determined to solve the problems inherent in the existing building. As well as an underused basement and ground floor retail that wasn’t well connected to either the street or the tube station, the office space was outdated with confusing entrances and inefficient layouts. This was solved by cutting and carving the structure to reconfigure the core and provide a central point of access.

Tom Smithers, Property Director at AshbyCapital, commented: “With the built environment contributing about 40% of the UK’s carbon footprint, it’s imperative that investors and developers look beyond the operational carbon footprint of their buildings to the emissions produced in the construction process and embodied carbon. Working with WSP to reuse and repurpose as much of the previous building as possible, we have reduced embodied carbon at The Kensington Building by 30% compared to a typical new-build office, proving that the construction of new office buildings doesn’t have to be environmentally damaging.”

For our team, the added challenge was designing these interventions while meeting the architect’s vision for the existing and new structure to be exposed with carefully coordinated services on show. With the plates and bolts joining old structure to new visible for all to see, this is a building that celebrates its story of reuse and adaptation. It’s proud of the benefits that reusing existing structures can bring – for occupants, the community, the client and the environment. And it points the way to a future where marrying old and new to create reused, repurposed low-carbon buildings is commonplace.

List of services WSP provided:

Structural Engineering
Fire Engineering
MEP
Geotechnical Engineering
Vertical Transportation Engineering Energy and Sustainability
Façade Engineering
Façade Access Engineering Transport and Development Acoustics
Ecology

Sustainable Development Goal 7 - Affordable and Clean Energy Sustainable Development Goal 9 - Industry, Innovation and Infrastructure Sustainable Development Goal 11 - Sustainable Cities and Communities