41 Peartree Street


The development at 41 Peartree Street in London saw the construction of a fifth floor penthouse apartment on an existing residential block. ByrneLooby were appointed to undertake a feasibility study to check the structural capacity of the existing building. The detailed structural design of the new apartment was constructed from a proprietary timber panel system supported on a steel grillage to transfer the loads to the columns of the existing structure.

To prove the capacity of the existing building, ByrneLooby were able to utilise enhanced column capacity by employing the age related strength gain of the concrete and to demonstrate that the basement slab was able to add to the pile capacity by raft action.

ByrneLooby also helped develop a construction sequence which would minimise impact on the existing tenants, a main concern of the client. This design saw the timber shell of the structure fabricated off site and set in place before the lift shaft and stair core were extended into the new apartment. This enabled the most disruptive work to be limited to a week programmed to coincide with residents’ holidays. ByrneLooby have also provided structural advice for the redevelopment of ground floor plant space in the block to form another apartment. 

ByrneLooby were also involved in a similar project at an adjacent block on Seward Street in London, where an existing development was to be extended with new penthouses on the 6th floor. When completed, the two new apartments would provide 2400sq ft of living space along with roof terraces providing spectacular views across the City.


“Silvertown Properties are maximising their property portfolio in Clerkenwell with a range of extensions and conversions and it was a great opportunity to be involved. As a Director with ByrneLooby, I was delighted to be involved in the project and the company was delighted to be their structural engineer for these works.”

Richard, Director


Project Photos