The Vision
The Chancery Rosewood represents the sensitive reinvention of one of London’s most recognisable modernist landmarks. Formerly the United States Embassy at 30 Grosvenor Square, the Grade II listed building – designed in 1960 by Eero Saarinen – has been transformed into a world-class luxury hotel and cultural destination in the heart of Mayfair.
Developed by Qatari Diar Europe in partnership with Rosewood Hotels & Resorts, and reimagined by David Chipperfield Architects, the scheme balances preservation with contemporary intervention. Reopened in September 2025, the hotel provides 144 suites, eight restaurants and bars, a state-of-the-art ballroom and the Asaya® Spa, all within a building that directly addresses Grosvenor Square and its surrounding heritage assets.
The ambition was clear: to deliver exceptional five-star hospitality while safeguarding the architectural integrity and civic presence of a globally significant landmark.
Our Contribution
Hilson Moran was appointed at pre-planning stage, working alongside the architect, AKT II and the wider consultant team to define the brief and establish robust engineering strategies capable of supporting modern luxury hospitality within a tightly constrained listed structure.
Key heritage elements – including the Portland stone façade, cruciform perimeter columns, the dramatic first-floor diagrid ceiling and the landmark eagle sculpture – were retained and celebrated. The building was reconstructed and extended to form an eight-storey hotel, with a new rooftop pavilion and a significantly deepened basement accommodating the ballroom, spa, swimming pool and plant areas.
Within the constraints of the retained diagrid structure and limited core space, we developed a highly coordinated building services strategy. All major plant, including heat rejection equipment, was located below ground to preserve rooflines and views. Innovative thermal storage solutions were introduced to manage peak loads, and a vacuum drainage system was adopted to avoid deep service zones and maximise floor-to-ceiling heights.
Our infrastructure team also led the complex utility diversions required to enable the basement expansion beneath Grosvenor Square, including relocation of UKPN substations, protection of strategic 33kV cables and coordination of multiple telecoms and statutory services in one of London’s most congested locations.
Design for People
The transformation reopens the building to the city, replacing a formerly security-focused perimeter with a permeable public realm that reconnects Grosvenor Square to Mayfair.
Internally, a new full-height atrium draws natural light deep into the plan, enhancing wayfinding and creating a calm, generous arrival experience. Carefully integrated building services support exceptional acoustic comfort, thermal stability and air quality across guest suites, restaurants, spa and event spaces.
By locating plant below ground and optimising distribution within constrained cores, we maximised usable space and ceiling heights throughout, ensuring that operational performance enhances – rather than competes with – the architectural vision and guest experience.
Design for Planet
Sustainability was embedded from the outset. The project has achieved BREEAM Outstanding – the first five-star hotel globally to do so.
Significant embodied carbon savings were realised through retention and reuse of the existing structure and façade. Extensive façade modelling informed upgrades that improve thermal performance while preserving the building’s distinctive character. Passive design measures, water conservation strategies and efficient energy systems further reduce operational impact.
The Chancery Rosewood demonstrates how heritage-led regeneration and environmental leadership can align — setting a benchmark for the adaptive reuse of modern landmarks in a low-carbon future.
