Homes England - Northstowe development

Project summary

Northstowe is a major residential-led development eight miles northwest of Cambridge City. Phases 2 and 3, the final phases of development, are by Homes England. Over the next 20 years, the former RAF airfield site and surrounding land will be transformed into a thriving new town community of around 25,000 people, featuring 10,000 new homes, multiple high-quality community facilities and commercial space, all carefully knitted together with natural assets and a new town centre.

CR Civil Engineering, an RSK Group company, is working for CR MacDonald, who are the principal contractor, to deliver the site preparation work for Homes England and project manager and designer, Arcadis. The CR Civil Engineering project work across 25 hectares of the wider 165-hectare site started in September last year and competed in August. 2025.

The purpose of the project was to clear, remediate and carry out a large earthworks operation at the old RAF base to support Homes England unlocking land for future housing development.

The background

The Northstowe remediation and enabling works are fundamental to producing urgently needed housing and infrastructure in the region. By safely remediating 20 hotspots of contaminated soil, clearing obsolete Ministry of Defence infrastructure and raising and preparing the land for development, this project has transformed part of the disused RAF base into a viable, development-ready site. The work has not only de-risked the site for Homes England and future developers but has also ensured that environmental and ecological priorities were embedded at every stage.

Multidisciplinary approach/strategy

The CR Civil Engineering team was able to successfully integrate the required environmental emphasis by working with RSK Group companies RSK Raw (providing environmental consultancy and remediation services), ATV Contract Services (vegetation clearance and ecological supervision) and Central Alliance (ground radar surveys).

All redundant infrastructure has been cleared (including building foundations, drainage, utilities, low value vegetation and topsoil) and the waste material produced has been processed for reuse on-site or for recycling. Only the contaminated waste and scrap steel has been removed from site to a specialist waste processing centres prior to reuse.

The scope of work was as follows.

• Site surveys, establishing site setting out controls
• Site clearance of existing topsoil, vegetation, hardstanding, roads, below ground structures, including drainage utilities and footings/foundations, fencing and former Ministry of Defence features
• Ecologically sensitive tree protection works, including retention of trees designated for potential incorporation into the permanent works or subject to tree preservation orders
• Compliance with ecological management plans, including the use of sensitive tree clearance methodologies
• Creation of a materials management plan and remedial implementation plan, agreed with the overseeing organisation
• Remediation of contaminated ground identified and encountered during earthworks, including on-site treatment and, where necessary, disposal off-site to specialist treatment facilities prior to reuse. As part of the site clearance, over twenty individual areas of contamination were identified, appraised, treated and/or removed for off-site treatment and reuse.
• Earthworks, including materials placement, relocation and import to raise land to a permanent earthworks strategic engineering level to facilitate future housing developments
• Treatment of soils, materials and hardstanding for reuse where appropriate

The challenges

The team made a commitment to embed environmental and ecological best practice into its project plan from the outset. Challenges addressed as part of this commitment included the management and processing of 80,000 tonnes of surplus concrete, brick and soils and the careful management of both mature and young trees on the site.

The solutions

As part of CR Civil Engineering’s waste and resource management strategy, the team was able to put more than 80,000 tonnes of surplus concrete, brick and unsuitable soils back into use as fill by processing all the material on-site using crushers and screening to produce usable (6F5 and Class 2) fill, therefore avoiding transporting a huge quantity of waste for off-site disposal. Only the contaminated waste and scrap steel has been removed from the site and sent to specialist processing centres for further treatment and reuse.

The team has also retained 11 hectares of mature trees, with more than 50 young trees also kept for potential future translocation. The project has remediated 20 individual areas of contaminated land. These efforts all support the broader sustainability goals of the Northstowe masterplan.

The impact

The Northstowe project is a great example of how civil engineering expertise can support effective regeneration, bringing significant areas of brownfield land back into use and helping to address the UK’s housing shortage.

While biodiversity net gain rules require a 10 per cent improvement in biodiversity pre- and post-development, Homes England is committed to exceeding this target and achieving 15% on later phases of development at Northstowe. Supporting this, over a third of the town is designed as publicly accessible open space, with new habitats and lakes created throughout the town to attract wildlife.

As such, this project represents a critical early phase in unlocking one of the UK’s largest sustainable housing developments.

By drawing on our in-house expertise in complex site remediation, ecological compliance and large-scale earthworks, we’ve enabled Homes England to bring this land to market safely and sustainably.