Following a detailed geotechnical review, SPEEDECK recommended a CFA piled raft solution as the most efficient and technically suitable approach. This design integrated the piling and slab as one substructure package, eliminating multiple trade interfaces and minimising excavation. Heave protection was required across all plots, and 225 mm voidformers were specified to mitigate uplift forces from the clay soils. The result was a streamlined, low-risk solution that supported both programme certainty and construction efficiency.
Concept Design
Design Engineering
The foundation was designed as a 225 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 380 kN, with pile lengths ranging from 6.0 m to 9.0 m. The total raft slab area across the development measured 427 m², delivering a single, durable substructure that minimised movement and reduced overall material volumes.
Construction
SPEEDECK completed all piling and raft construction as one coordinated substructure package, simplifying sequencing and improving quality control. Plots were constructed on an engineered concrete working platform. The works were delivered safely and efficiently within the agreed programme, reducing excavation and spoil disposal volumes on site within the six week construction programme. This approach provided a level, durable platform ready for immediate superstructure works, improving downstream productivity for the client.
