
Scope of works
Construction of superstructure featuring architectural finish columns and exposed soffits. Other works include excavation of substructure lift pits, construction of basement and ground floor structure and integration with roof top steel frame.
Project Aleph is a landmark redevelopment of Lansdowne House at the southern end of Berkeley Square, Mayfair. It has been designed by architects AHMM with a nod to the classical architecture of the original and surrounding buildings.
The project will see the delivery of a highly complex concrete frame, one that features over 350 pre-cast concrete columns which not only form the exterior façade but also feature internally. The columns are being deliberately exposed, allowing the concrete to serve as a defining architectural feature.
Kilnbridge is delivering the superstructure which comprises of two basements levels and an eight-storey reinforced concrete frame with a terrace at level 8. At the eighth floor the frame transitions to a two-storey steel frame and a roof top plant room.
The main frame comprises of pre-cast concrete wall panels with the steel frame featuring composite slabs. Post-tensions slabs are being installed from level 1 to level 8.
The floor slabs on levels 2 to 7 have been fabricated to allow a Thermally Activated Building System (TABS) to be installed. This will provide cooling during the summer months to counter the heat the thermal mass of the building will generate.
Befitting its Mayfair location, the building’s design emphasises architectural finishes, with exposed concrete elements forming a central part of the aesthetic vision. The concrete frame is not merely functional but central to the building’s identity.
The architectural pre-cast concrete columns will form a tree like structure with exposed finishes and detailed soffit recesses elevating the frame to a hero feature of the design. In total 496 precast columns are being installed with exposed internal concrete soffits from levels 1 to 8.
Delivering an architectural finish across a building of this size and complexity requires detailed design, precision engineering and meticulous planning. Each column is being cast off site and delivered to site. Due to the size of the columns and the nature of the finish, special measures have been employed by the site team to ensure the integrity of every column during crane lifting.
The buildings frame has been designed around a ‘long life, loose fit’ concept. This provides generous floor plates with an independent, centralised core. This means that in the future, as the needs of the building occupants changes, it can be reconfigured and adapted without the need for extensive demolition and associated environmental impact.
The building has been designed to achieve the highest possible standards for sustainability and wellbeing, targeting BREEAM Outstanding and WELL Platinum.
Berkeley Square in Mayfair, is one of London’s most prestigious addresses. With space at an absolute premium, logistics on the project require careful planning and meticulous execution. Throughout the project Kilnbridge will be liaising with main contractor Mace and Westminster Council to ensure disruption to kept to an absolute minimum with site deliveries carefully planned and co-ordinated.

Outcome
This project demonstrates how reinforced concrete can deliver both structural integrity and architectural distinction. It illustrates Kilnbridge’s ability to manage complex structures with care and precision. By integrating exposed finishes and high specification pre-cast elements, the building will achieve a modern, striking appearance while meeting functional and environmental performance goals.
Once completed the 10-storey building will deliver 225,000 sq ft of office space and 14,000 sq ft of retail and restaurants, complemented by balconies on every floor and a rooftop terrace.