Feature Project: 1 Derry Street

Concrete encased cast-iron columns, unexpected raft foundations, extensive services, TFL constraints, trees with TPOs, and an under utilised roof…

We picked up this project at Stage IV under D&B, and unfortunately the previous team hadn’t had the benefit of intrusive investigation works. This threw up a few challenges, but nothing we couldn’t overcome.

We switched from an expensive below ground attenuation tank to a blue roof. The loading from which was mostly offset by the new roof terrace and plant areas being built up off a steel grillage. With a bit of research, intrusive investigation, and material testing, we’ve also been able to reduce the extent of column strengthening by 50%. We also omitted the CFA piles (which would have been challenge adjacent the train tracks), in favour of more sustainable screw piles. That’s not to mention the circa 20% saving on steel tonnage that we’ve managed too!

This project was a real example of how experience and lateral thinking can simplify a solution to the benefit of all parties.