Old Oak Common foundations complete after 91 pours

Balfour Beatty Vinci Systra joint venture (BBVS) has completed the foundations at Old Oak Common.

The 850-metre-long underground station base, which will house six platforms for high-speed trains, has been constructed using 76,000 cubic metres of concrete and 17,000 tonnes of reinforced steel.

The base slab covers 45,000 square metres and is nearly two metres thick at its deepest point. Construction began in April 2023 and required 91 separate concrete pours to complete.

At peak construction, the base slab works employed up to 50 steel fixers and 20 joiners, supported by a team of engineers.

HS2’s project client for Old Oak Common, Peter Gow, said: “Completing the base slab of the underground station box is a key milestone in building HS2’s new super hub station in West London. This is the final stage in completing the foundations for the high-speed station, and will be where HS2 tracks are laid, platforms are constructed and the station building and roof and built above.

“At Old Oak Common we are making significant progress in building this state of the art, environmentally friendly, transport hub which will be a key part of the HS2 route.”

The excavation of the box was completed in the summer of 2024 with subcontractor Expanded – a Laing O’Rourke company – removing 1.3 million tonnes of London clay. To create the base slab, the team installed blinding, layers of shingle for drainage before a matt could be laid on top. Then a 1.85 metre high reinforcement layer was installed– with the team fixing the steel by hand. Finally, concrete was poured to compete the slab, competing the foundations for the high-speed station area of Old Oak Common.

Holcim subsidiary London Concrete supplied the concrete used to complete the base slab from a special batching plant set up on site. More than 90% of the concrete used for the base slab was mixed on site.

BBVS project director Steve O’Sullivan said: “With the completion of the base slab, we have achieved another significant milestone at Old Oak Common. In less than two years, we have carried out 91 concrete pours of between 600 m³ and 1,000 m³ each. Logistically, this has been a huge undertaking, requiring detailed planning and collaboration between HS2, Balfour Beatty Vinci Systra and our supply chain partners. This latest step will enable us to progress to the next phase of works, with construction of the high-speed platforms already underway”. 

Work is now under way on the six HS2 service platform with wall frameworks being installed ready for concrete pouring. The high-speed platform slabs are currently being manufactured by Explore in Worksop and installation will begin this spring.

The team is also working above the base slab to construct the ground floor level of the station before the superstructure can be built.

Tunnelling work to connect the station to the HS2 network is being done by Skanska Costain Strabag JV. In the eastern section of the box, the team are preparing to launch two giant tunnelling machines towards Euston, where a more central London terminus will be built if private money can be found for it. In the western side of the box, the team will excavate the tunnel using the sprayed concrete lining method.

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