Project Brief
Phase 3 of the Moss Nook development forms part of a wider regeneration masterplan for a 95-acre former colliery site in St Helens. This phase comprises the construction of approximately 300 affordable homes using traditional methods across 19.5 acres of brownfield land. The scheme received partial funding from Homes England.
Adept was appointed to deliver post-planning, detailed civil and structural engineering design services. The scope included technical approval of Utilities Section 104 and adoption of carriageways via a Section 38 agreement. Adept continues to support Watkin Jones through the construction phase to handover.
Solution
Adept inherited a planning-approved design developed by others. As the design progressed toward adoptable standards, it became evident that the approved layout and site levels did not interact optimally. The initial design required the import of 30,000m³ of clean fill material. By thoroughly assessing the remediation strategy and existing ground contamination, which included galligu, asbestos, and high chemical concentrations, Adept developed a revised highway levels strategy. This approach successfully avoided highly contaminated areas and enabled excavation in others, thereby correcting the earthworks imbalance and eliminating the need for imported fill. Adept also provided detailed design services for road and drainage infrastructure, coordinated with statutory undertakers and local authorities, and supported the client through the Road Safety Audit process.
Value Engineering
The revised highway levels strategy was a key value engineering intervention. It allowed the team to work within the constraints of the contaminated ground while achieving compliance with adoptable standards. The strategy enabled the reuse of on-site materials and avoided unnecessary excavation in sensitive areas. This ensured that the design remained practical, cost-effective, and aligned with the construction programme.
Cost Saving
The elimination of the need to import 30,000m³ of clean fill material resulted in a cost saving of approximately £300,000. Additional savings were achieved through the optimisation of foundation and slab design, and by aligning Section 38 and Section 104 approvals early in the process to avoid delays and rework.
Social Value
The project contributes to the delivery of affordable housing in a high-demand area and supports the long-term regeneration of a previously derelict site. It creates opportunities for local employment and SME engagement and enhances community infrastructure as part of the broader Moss Nook masterplan.
Environmental Impact
The reuse of brownfield land significantly reduces the environmental footprint of the development. The revised earthworks strategy minimised the need for imported materials and reduced carbon emissions associated with transport and material production. Sustainable drainage principles were incorporated into the design, and previous remediation works were verified and integrated into the engineering strategy.
