The sheer scale of this cut and carve remodelling project in central London gave Nick Donovan a big stage to parade his talents on.
Nick set the scene early in preconstruction, by managing to negotiate with the council a full pavement closure to accommodate a scaffold gantry during the entire build, saving weeks in demolition programme and offering by far the safest option. All other projects on site nearby at the time were required to keep the footpath open. And by hiring the temporary works equipment direct and procuring an installation specialist, he saved a further £200,000.
As prices and specifications came in from manufacturers for the new 13-people lifts, Nick noticed a difference in their dimensions that made the one-size-fits-all design for the new lift shafts potentially overgenerous. With net internal area a key success measure for the project, his identification of a space-efficient lift cabin allowed a lift shaft downsizing that added 18sqft per floor – a 2% increase in lettable floor space.
The lift shafts themselves were seven-storey precast units hoisted in by a 300-tonne crane (sited on that closed road) in just four days. His driving of this solution also took seven weeks off the programme.
After the first cost estimate made clear that the original intention to remove 75% of internal structure was not an option, he rationalised the structure to reduce the amount of demolition. He asked a cleaner contractor he had worked with previously to review whether some of the opening windows could be cleaned from the ground. When the review concluded that all the rear windows could be serviced from the rear extension roof, he saved £300,000 by making them all fixed-pane. Meanwhile his decision to build the two-storey rear extension on a raft foundation 100mm shy of a 6m-high party wall avoided costly underpinning and legal agreements.
But perhaps the biggest in Nick’s long train of technical victories was his insistence that the contractor for the new structural steel attend site (along with the design team) to review the exposed as-built existing frame to ensure the design team’s assumptions matched up with reality. They didn’t. The client’s cloud point survey had been conducted before the strip-out works had been completed, and additional angles were subsequently revealed within the soffit, meaning existing metal decks were at differing heights, requiring new floor-slab connection points to the precast lift shaft.
Getting the design amended proved challenging, involving a change in column locations and deck orientation, and the binning of virtually all the proposed connection details. What was supposed to be a simple bolt-on design became a full on-site weld installation overnight. It did, though, eliminate the inevitable irritation that would have otherwise resulted from having to redo so much of the works.