Innovative design allows upwards extension & triple basement construction

The famous Claridge’s Hotel in Mayfair was built before the turn of the century and extended during the Art Deco era in 1928. The hotel was extended upwards with the addition of three new floors and a triple basement beneath the existing Art Deco extension of the hotel.

With this constraint in mind an innovative solution was developed by Walsh, working closely with geotechnical engineers.

The design included new foundations to be installed at depth in tunnels within the London Clay. Columns were then to be jacked up to the underside of the existing raft at locations corresponding to the existing steel stanchions above. With the building then supported off the new footings at depth, the basement could be excavated using top-down construction techniques.

A complex heave and settlement analysis was undertaken to study the impact the large excavation would have on neighbouring buildings and infrastructure. Soil nailing, traditional underpinning, and Jet Grouting Underpinning of an existing contiguous pile wall are techniques that we included to maintain the structural integrity of the adjacent buildings.

  • Claridge's Hotel
  • Michael Blair Associates
  • McGee
Completion Date2020

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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.