Following geotechnical review and ground modelling, SPEEDECK proposed a CFA piled raft system to provide consistent bearing across variable strata while minimising excavation. The design integrated the piling and raft slab as one substructure package, reducing trade interfaces and accelerating overall delivery. The solution eliminated the need for deep trench fill foundations, protecting the programme and reducing waste movements on site.
Concept Design
Design Engineering
The foundation was designed as a 300 mm reinforced concrete raft supported by 300 mm diameter CFA piles, designed in accordance with Eurocode and warranty standards. Piles achieved a maximum safe working load of 630 kN, with pile lengths ranging from 6.0 m to 14.0 m. The raft, covering a total area of 926 m², incorporated pile caps and localised waterproofing provisions to support lift pits and balcony posts. The ground investigation confirmed the shallow chalk deposits required no heave protection, allowing for a straightforward, non-voided solution.
Construction
SPEEDECK delivered all piling and raft works as a single integrated substructure package, streamlining sequencing for drainage and underslab services. The consolidated scope minimised on-site coordination and provided a safe, clean, and level working platform ready for the superstructure. This efficiency enabled McCarthy & Stone to maintain programme certainty and achieve earlier follow-on access, supporting timely project delivery.
