25 Berkeley Square is a Grade II listed building in the heart of Mayfair, overlooking one of London’s most historic green spaces. Designed in 1906 by Frank Verity in the Beaux-Arts style, it was originally home to luxury mansion apartments before being converted to offices in 1954. By the 1990s, much of the building had been reconstructed, but key historic elements remained. Over time, however, the interiors became outdated, failing to meet the needs of modern businesses. The challenge was to respect its heritage while enhancing its sustainability and functionality.
25 Berkeley Square
London W1
Honouring the past, building for the future
Retaining heritage, reducing carbon
- Preserved original structure where possible, reducing embodied carbon.
- Replaced three non-historic top floors and roof with a new lightweight mansard extension, improving energy efficiency while respecting the building’s character.
Sustainable materials and energy efficiency
- Westmoreland green slate roof – a natural, sustainable material found on heritage sites like Buckingham Palace.
- Portland stone cladding – lighter and more carbon-efficient than solid stone, reducing transport emissions.
- Original timber windows restored where possible; newer sections upgraded with high-performance double glazing to reduce energy use.
- Air-source heat pump installed on the ninth floor to power the building sustainably.
- LED lighting throughout and open-plan office spaces designed to maximise natural light.
The impact
- BREEAM ‘Excellent’ rating for sustainability.
- A significant reduction in carbon footprint by focusing on retention over reconstruction.
- A modern, energy-efficient workspace that blends history with cutting-edge sustainability.
- Enhanced occupant wellbeing by balancing open-plan efficiency with preserved heritage rooms overlooking Berkeley Square.
Our redesign brought 25 Berkeley Square back to life, blending its rich history with modern sustainability. This transformation ensures it will continue to serve businesses and the community for generations to come.
