The demolition of an existing building to make way for a high-end residence in the Arts and Crafts style, more in keeping with other properties on Palace Green, and the first major new building to be constructed on this very high-profile street in more than 50 years.
The main house is set out over five-storeys, including a double-storey basement which extends beyond the footprint of the main house superstructure and contains a swimming pool and other leisure facilities, as well as a large catering kitchen. At ground floor a new covered winter garden with complicated exposed steelwork framing has been included.
A very tight site with sensitive neighbouring structures meant that constant movement and vibration monitoring was required during the basement construction. The basement wall is a secant pile wall, and an unexpected and late change to a temporary works design that used props above ground floor level, to aid the sequencing of the slab pour, meant the capping beam was subject to complicated torsional forces. At very short notice we coordinated directly with the subcontractor to ensure that the thrust blocks and reinforcement detailing were both adequate and buildable on the tight site. This saved an expensive delay and was hugely appreciated by the contractor.
Relatively complicated roof geometry, dictated by the planners and rights of light requirements, was subjected to several value engineering sessions. We looked at many schemes which variously used, or avoided, cranked beams, and maximised or reduced on site welding and cut timber structures to finally arrive at a scheme which used elements of all of these while still meeting the architectural requirements, staying within the cost plan and programme. We enjoy this type of challenge; conflicting constraints meant there was a risk of arriving at a complicated and inefficient solution piecemeal and by slow evolution. Instead we took the lead to help the team look at the problem as a whole and find the right solution, much to everyone’s satisfaction.