IN Brief:
- Legendre UK has been appointed for the £70m redevelopment of 50 Stratton Street in Mayfair.
- The all-electric office scheme will use lightweight steel and four new cross-laminated timber floors.
- The project adds to London’s growing pipeline of complex low-carbon commercial refurbishments.
Legendre UK is preparing to start main construction on the £70m redevelopment of 50 Stratton Street in Mayfair, delivering a major commercial repositioning for Berkeley Estate Asset Management.
The project will create a 135,000 sq ft office building designed by Stiff + Trevillion, with large 12,000 sq ft floorplates, high-quality finishes, communal and private terraces, and an all-electric services strategy. Construction is expected to begin in June, with completion targeted for mid-2028.
The scheme is targeting BREEAM Outstanding and LEED Gold, placing it within the higher tier of London commercial refurbishments. Its structural approach includes lightweight steel and four new cross-laminated timber floors, allowing the building to be expanded and upgraded while supporting a lower embodied-carbon strategy.
Prime office redevelopment in London is increasingly being shaped by retained structure, upgraded services, stronger amenity, and clearer environmental performance. Developers and asset managers are under pressure to provide workspace that can compete for occupiers while addressing carbon, planning, and certification requirements that have become central to commercial value.
Legendre’s appointment follows its separate London office refurbishment win at 10 Salisbury Square, where the contractor is delivering another low-carbon commercial scheme in the capital. Together, the projects show the company moving deeper into constrained, design-led office redevelopment rather than straightforward new-build delivery.
Projects of this type are technically demanding because the retained building has to be made to work with new structure, new services, modern workplace expectations, and enhanced sustainability targets. Existing buildings bring unknowns in tolerances, surveys, structural capacity, façade condition, party walls, services routes, and sequencing, all of which can challenge programme certainty once work is under way.
Mayfair adds further pressure through limited construction logistics space, high-value neighbouring assets, planning sensitivities, and demanding tenant expectations. The finished building will need to justify its position in a competitive prime market through specification, amenity, comfort, operational performance, and the credibility of its environmental credentials.
The all-electric strategy also reflects a broader move away from gas-led commercial building services, particularly in schemes targeting strong sustainability ratings. That places more weight on electrical capacity, plant coordination, controls, metering, resilience, and the integration of efficient heating and cooling systems within an existing urban building.
For contractors, the commercial retrofit market is becoming a specialist discipline in its own right. Success depends on more than careful strip-out and high-quality finishes. It requires early engagement with structural engineers, MEP designers, façade specialists, sustainability teams, landlords, and future occupier requirements, all while protecting programme and cost certainty on a tight site.
50 Stratton Street adds another substantial scheme to London’s low-carbon office pipeline. The project also underlines how commercial refurbishment has moved from a defensive asset-management decision into a core route for creating premium workspace in areas where new-build opportunities are limited and carbon expectations are rising.
