Studio DERA has completed a project to adapt a house in Belgravia, which it has extended, reworking a disused swimming pool to accommodate two new floors of living space. The extension includes a master suite, lounge, utility room and sunken courtyard, which brings light deep into the floorplan.
The scheme has not altered the historic frontage of the terraced house, which has a rich history. Mozart is believed to have composed his first symphony there at the age of eight, while architect Edwin Lutyens combined two houses into one before the writer Vita Sackville-West moved there with her husband Harold Nicolson in 1914.
The scheme leaves the historic building visually dominant with the new extension intended to read not as a single block but as a series of terraces, voids, lightwells and planted rooms. These use a deliberately neutral material palette consisting of travertine, GRC concrete and timber linings.
Architect’s view
Mozart House already contained its own history of change. We decided to build on this by developing a sequence of internal and external spaces, carving into the garden and below ground, then using terraces, a colonnade and a sculpted lightwell to bring daylight, air and greenery into the house.
Our ambition was not simply to create a more generous space, which was the clients’ primary need, but to make it feel fully integrated with the existing Georgian parts of the house, while keeping it light, modern and visually interesting. The progression of interconnected rooms and courtyards creates a gradual transition from the original interiors, through the new rooms and on into the garden.
Our material palette of travertine, GRC and timber helps anchor this relationship between old and new. We wanted the extension to feel less like an insertion and more like an evolving stage in the house’s history, building on the adaptive changes made by former owners. In this way, its historical value is recognised and embraced while allowing its form and aesthetic to grow.
Marcel Rahm, director, Studio DERA
Client’s view
The brief was to transform a disconnected and underused part of the house into something fully integrated with our daily life. The existing pool area had become dark, awkward and detached from the rest of the home.
Studio DERA’s response was not simply to add accommodation, but to rethink how the rear of the house could work spatially. From the outset, the practice understood the complexity of the project: listed fabric, excavation, garden levels and natural light all had to be resolved together. The process was rigorous and collaborative, with drawings and models helping us understand how the courtyards, rooms and routes would connect.
What is most striking in the completed house is the quality of the spaces. Although much of the new accommodation sits below the original garden level, it feels bright, generous and closely connected to the outside. The sequence of courtyards has changed how the house is used, making the rear of the building feel central rather than secondary. The result is understated, but genuinely transformative.
Project data
Location Ebury Street, Belgravia, London
Completion date August 2025
Gross internal floor area 524m²
Additional floor area 85m²
Procurement route Private client
Architect Studio DERA
Client Private
Structural engineer Structural Design Studio
Landscape consultant FFLO
Main contractor JK London Development
Environmental performance data
Design life 60 years
Embodied carbon Design-stage estimate (RIBA Stage 3) 262,000 kgCO₂e
Whole-life carbon Design-stage estimate (RIBA Stage 3) 1,340 kgCO₂e/m²