5 & 6 St James’s Square, London, SW1
Exemplar Properties
70 weeks
£8m
City of Westminster
Overview
No. 6 was the former head office for Rio Tinto, a modern 6-storey reinforced concrete structure in the heart of St James’s Square, neighbouring the In & Out Club. This building wrapped around the Grade ll listed No. 5 St James’s Square, the former Libyan Embassy, which was to be maintained throughout demolition. John F Hunt delivered a carefully engineered excavation and heritage protection package that enabled deep basement construction while safeguarding neighbouring listed structures.
Relevant Experience
A highly controlled phase of basement excavation and temporary works followed the completion of demolition, ensuring seamless continuity into the reinforced concrete construction phase.
A carefully sequenced excavation strategy was agreed with the RC contractor and temporary works designers, enabling efficient progression while safeguarding neighbouring assets and maintaining full structural stability across the site.
The reduced-level dig extended 11 metres below ground, with 12,000m³ of material expertly removed and 300 tonnes of structural steelwork installed to support the evolving basement structure.
To overcome the physical constraints of the site and maintain productivity, our team designed and constructed a bespoke cantilever platform, providing a safe and elevated working deck for a specialist long-reach excavation machine.
This bespoke solution enabled materials to be removed from deep excavations and loaded directly onto lorries at upper levels, significantly improving logistics, safety and efficiency.
Neighbour protection was paramount throughout. The prestigious In & Out Club, located immediately adjacent to the site and renowned for its ornate heritage interiors, was subject to rigorous monitoring pre-works, during, and post-works.
No movement was detected at any stage, reflecting the care, expertise and proactive risk management strategies implemented by the team.
Working in close proximity to listed features required a highly sensitive approach, with hand demolition techniques adopted wherever mechanical methods posed a risk.
All heritage-sensitive areas were monitored continuously, 24 hours a day, ensuring immediate response capability and absolute assurance for stakeholders.
Our tenant liaison manager worked with Westminster Council and the local residents throughout the works to ensure a good relationship was maintained at all times.
