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8 Bleeding Heart Yard (20-23 Greville Street)

London, UK

º£½ÇÊÓƵ’s contribution to 8 Bleeding Heart Yard helped transform an ageing and unremarkable 1970s office building into an award‑winning workplace that balances architectural imagination with environmental responsibility.

Our team brought a clear focus on elevating performance, strengthening sustainability outcomes and enabling an ambitious deep retrofit that now stands as a benchmark for sensitive, future‑ready development within a conservation area.

The project formed part of a wider architectural reimagining of the site led by Groupwork and commissioned by Seaforth Land. Once defined by a flush‑fronted and uninspired mid‑century facade, the building has been reconceived as a contemporary workplace wrapped in a playfully abstracted interpretation of the Victorian streetscape that once occupied this plot. A new metal veil, designed to evoke the rhythm and character of the long‑demolished buildings, creates a striking interplay between solidity and transparency.

The result has been widely celebrated, securing a RIBA London Award and a RIBA National Award in 2025 for its thoughtful retrofit strategy and architectural innovation. Situated in the heart of Hatton Garden, the scheme enhances an established conservation area while delivering contemporary office accommodation that responds to modern expectations for comfort, environmental performance and character.

º£½ÇÊÓƵ supported this transformation through a multidisciplinary scope, including facades, sustainability and BREEAM assessment, acoustics, security, waste and vertical transportation, along with design input on fire strategy and material choices to ensure the development met regulatory requirements and client ambitions.

We enhanced the building’s performance by shaping a high‑efficiency facade strategy that improved insulation, airtightness and long‑term energy use.

Our team enabled the architectural ambition by resolving the complex metal veil geometry and ensuring safe, buildable facade connections.

Our experts strengthened sustainability outcomes through BREEAM leadership and coordinated modelling that supported very low operational energy demand.

Challenge

Retrofitting an existing 1970s structure in a dense urban context brought a series of interconnected challenges, beginning with the limitations and performance issues of the original building envelope. The pre‑existing facade was thermally poor and no longer fit for purpose, making operational energy performance a fundamental constraint. The design ambition to wrap the retained structure in a new metal veil raised questions around constructability, geometry and detailing, particularly as the form drew inspiration from historic Victorian architecture but relied on contemporary manufacturing techniques.

Working within a conservation area meant navigating a planning environment sensitive to alterations in scale, massing and appearance. Earlier applications by the previous building owner had been rejected, underlining the need for a design rooted in a stronger relationship with the historic character of the neighbourhood. The challenge lay in creating a facade that engaged with this historic context without resorting to pastiche, and which could be delivered economically and robustly on an existing structural frame.

The original structure also imposed constraints on vertical and lateral loads, particularly where new accommodation was planned at roof level. Introducing cross‑laminated timber (CLT) extensions reduced weight but required careful understanding of fire strategy in the context of a medium‑rise office building.

At the same time, the client sought to deliver significantly improved operational energy performance through measures such as enhanced insulation, airtightness and the integration of photovoltaic (PV) panels, requiring coordinated decision‑making around building services, envelope design and sustainability assessments. The design team also needed to reconcile the desired aesthetic of steel‑framed windows with the environmental realities of meeting modern thermal performance standards. Recreating the slender lines of heritage steel profiles risked condensation and poor U‑values unless advanced thermally broken systems could be identified, tested and incorporated without compromising the architectural intent.

Solution

º£½ÇÊÓƵ’s multidisciplinary support helped unlock the potential of the retrofit while ensuring the architectural vision could be realised with technical clarity and performance integrity. Our facade engineers collaborated closely with Groupwork to rationalise the complex metal veil that forms the defining external feature of the project. The veil draws on archival research into the Victorian shops, warehouses and townhouses that once occupied this narrow plot, with perforated metal screens projecting an impression of sculpted solidity from a distance while revealing their lightness and abstraction up close. Working with this unconventional facade required innovative analysis of fixing strategies, bracketry and the geometric requirements of formed metal components.

To address the shortcomings of the original 1970s envelope, our team developed a high‑performance facade strategy with improved airtightness, insulation and glazing performance. This included supporting the selection of window systems that combined a historical steel‑framed aesthetic with the thermal efficiency expected of contemporary office space. The design intent was preserved while significantly reducing the risk of condensation and heat loss.

The team led the project’s BREEAM assessment and contributed to modelling and evaluation to ensure the retrofit met best practice for operational carbon reduction. Measures integrated into the design include PV arrays, upgraded insulation and an airtight envelope that together deliver very low in‑use energy demands. Although º£½ÇÊÓƵ did not design the building services systems, our analyses and coordination helped ensure that the architectural and facade strategies supported the wider operational energy ambition.

Acoustic design, security consultancy and waste strategy were also integral to the project’s success. Our acousticians ensured the new facade and internal layouts delivered appropriate acoustic separation for high‑quality office environments, despite the constraints of the retained structure. Security specialists contributed to ensuring safe operation and access control within a complex urban footprint. Waste advisors helped shape an approach consistent with the client’s sustainability aspirations, minimising waste during construction and supporting efficient ongoing management.

Where CLT was introduced to form the new upper storeys, our team provided design‑stage advice relating to fire performance, material choice and the relationship between timber extensions and the existing concrete frame. This contributed to a safe and compliant strategy that enabled the client and architect to pursue the benefits of lightweight timber construction. Vertical transportation input ensured efficient circulation within the extended building, including within the retained core and new additions. Together, these disciplines aligned to enable a coherent, high‑performing retrofit that met both aesthetic and operational ambitions.

Value

º£½ÇÊÓƵ’s involvement helped the client achieve far greater value from the existing structure than demolition and rebuild would have offered, unlocking additional floor area while maintaining a significantly lower operational energy profile. Our advice supported an architectural vision that honours the historical narrative of the site without compromising contemporary standards for performance, safety or comfort.

By enabling the transformation of an underperforming office block into a distinctive, award‑winning workspace, we helped the client reposition the building commercially and environmentally. Our facade and sustainability strategies contributed directly to the scheme’s impressively low in‑use energy credentials.

Through sensitive retrofit, the project extends the life of a mid‑century building while adding new high‑quality workspace using low‑carbon structural materials. This aligns with broader industry priorities around retaining embodied carbon, avoiding unnecessary demolition and finding creative ways to revitalise existing assets. The result is a workplace that feels embedded in the history of Hatton Garden, yet equipped for the demands of the future.

Working with º£½ÇÊÓƵ on 8 Bleeding Heart Yard was an absolute pleasure and much more like a partnership. We were able to leverage their capabilities to maximise our outcomes in the innovative facade and architectural design as well as our very high architectural standards.

Tyler E. Goodwin, Seaforth Land Holdings Ltd