The project team behind the £142 million mixed-use scheme at Outernet London has overcome a major technical challenge.

A 'box within a box' auditorium was built at the site in challenging circumstances.

Due to the site being located next to Tottenham Court Road Station it is in close proximity to the Northern Line. The building's foundations also straddle the Crossrail tunnel, so the team is constructing an underground box within a box to contain a 2,000-capacity venue.

The team consisted of main contractor Skanska, along with Severfield, Orms Architects, Engenuiti and Buro Happold Acoustics.


They worked together seamlessly to lift the 400-tonne steel and concrete roof into its final position eight metres high using 14, 75-tonne jacks. After this, 70 perimeter columns were installed underneath so that the roof could be carefully released from the jacks onto the permanent columns.

Paul Roberts, Project Director at Skanska, explained: "We worked with our supply chain member, Severfield, to complete this technically challenging part of the project. The 'box within a box' will be acoustically and structurally isolated from the rest of the basement structure. This was achieved by building a steelwork and concrete box that sits on top of 200 acoustic packs in the basement.

"Since we began this project two years ago, we have faced many technical challenges, but this one is the biggest so far. The roof was only 5cm away from the surrounding structure while the jacking was taking place. These jacks are controlled by a system that is so accurate, it controls each movement to within 1mm."

The project is set to be completed at the beginning of 2020.

(CM/JG)