Calders Wharf

Seamless integration of engineering disciplines makes development viable

Calders Wharf in London is a four-storey residential block constructed directly above two Docklands Light Railway (DLR) tunnels. Walsh inherited this scheme from the incumbent engineers who had proposed large diameter rotary-bored piles to depths beyond the tunnels, taking loads into the underlying Thanet Sand. This is a recognised approach that works effectively where resale volumes can absorb the high foundation cost. However, in this case, planning limitations required low-rise/low unit numbers on this site, making the proposed development unviable with the large diameter bored piles.

Walsh approached the foundation design from a new angle, using our experience of building over other railway assets in London to value engineer the development. We proposed the use of a ‘compensated raft’ approach, constructing a sacrificial basement to offset the weight of the building. Net loadings and tunnel displacements were therefore reduced to agreed limits through an extensive and detailed liaison process with the DLR.

Extensive sub real-time monitoring of the tunnels was carried out throughout the construction process and it was observed that monitored displacements, both during construction and over the longer term, closely matched those predicted. This successful collaboration between geotechnics and structural design led to an economically viable development that now fronts the River Thames.

  • Telford Homes
  • PRP Architects
Completion Date2019
  • Tower Hamlets

Please click on images below to open a full-screen gallery.

Explore Related Projects

Student Accommodation

Chapter London Bridge

Innovating city student living through MMC [...]

Read more


83 Barchester Street

Revitalising a site of industrial heritage for modern living and community-focused design [...]

Read more


Paddington Green Police Station

Wind-tunnel testing and temporary works design reduces high-rise concrete volumes & embodied carbon [...]

Read more

Mixed Use

Harold Hill Family Welcome Centre

Structural scheme designed for future-proof adaptation [...]

Read more

Student Accommodation

Palmerston Court

MMC innovations & Passivhaus standards [...]

Read more


Springfield Hospital

Lean design delivers significant savings on time and materials [...]

Read more

Taking Sustainability Seriously

Sustainability is in our DNA and we have our own ambitious goals to achieve Net Zero as a business and with our designs. With innovative in-house monitoring tools, Walsh clients have seen on average reductions of 10-20% total embodied carbon, with some of our flagship work achieving 60-70% reductions compared with baseline figures.