Finchley Road
A new 3,000m² loadbearing lava stone building providing 22 homes above lower-level workspace in north west London. Using approximately 725 tonnes of granite from Larvik in Norway, the building is the first 10-storey self-finished stone structure, without the need for stainless-steel reinforcing bars or secondary structure, since the last stone cathedrals were erected.
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Client
317 Finchley Road Limited
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Architect
Groupwork
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Photography
Timothy Soar
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Project Manager
Pantelli
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Stone Suppliers
Lundhs, Ateliers Romeo
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Size
3,000m²
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Completion
2026
The building deploys the volcanic rock across 596 columns and beams. It has around 80% less embodied carbon than a steel frame clad in stone, and 55% less embodied carbon than a concrete structure clad in stone. The design also creates new landscaped, publicly accessible spaces, including a new footpath connecting the site to the nearby Finchley Road and Frognal Overground station.
The stone frame carries both the vertical and wind loading, freeing the internal spaces of heavy, restrictive core walls. The project is a rare contemporary example of a medium-rise building where the façade acts as both cladding and primary structure, reversing the separation of structure and envelope typical of modern construction. It also suggests an alternative low carbon vernacular of elegant stone frames supporting CLT floors.
The design process involved spending time with the design team, stone masons, and client selecting stone types that met structural, fire, cost, and aesthetic criteria. The primary material was selected after testing its fire performance against that of limestone at the British Research Establishment, where it was discovered that a granite exoskeleton required roughly half the amount of stone as a limestone exoskeleton due to its superior resistance to internal fracture during a fire.
The high-performance structural skin enables a true ‘fabric-first’ approach. Internal daylight is maximised and solar gains are controlled throughout the building with the use of moveable shading and efficient glazing systems, while MVHR units located within each residence further reduce heating requirements.
The building services strategy applies efficient lighting with daylight sensors and dimming, as well as high efficiency condensing boilers, a small-scale communal heat pump, and underfloor heating. The boiler controls allow for fast response to external temperature change, reducing the need for sudden demands of duty from the boiler. The strategy also incorporates a large south facing photovoltaic array at roof level to maximise on-site renewable energy generation.
The project was re-categorised as a high-risk building under the changes to the Building Safety Act during delivery. The stone structure, fire strategy, and building services design were subsequently reviewed and, where necessary, adapted under a high-level of external scrutiny to meet the additional regulatory, safety, and assurance requirements.
The scheme won planning permission in 2016 and, following delays due to change of ownership, started on site in November 2021. Webb Yates have been working alongside Groupwork from the earliest stages of the design, providing structural, civil, and building services engineering.
The project marks a series of firsts for both our practice and the wider industry, setting a new benchmark for how structure, fabric, and environmental performance can be brought together under many challenges and constraints.
Connection details and sway frame
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