Polypipe’s thermoplastic pipe products deliver vital infrastructure for UK’s largest selfbuild community

Polypipe has supplied a wide range of its thermoplastic pipe products for foul water management, delivering vital infrastructure to the innovative Graven Hill project site in Bicester, Oxfordshire.

The Graven Hill project is set to become the UK’s largest self build community, offering plots for 1,900 homes across the site, with accepted planning for further developments including a primary school, pubs, and convenience shops. The site, located on 188 hectares of land formerly owned by the Ministry of Defence, will provide purchasers with the chance to build their own home, with a focus on energy efficient materials, modular construction methods, and contemporary design.

As the UK’s leading manufacturer of sustainable drainage and water management systems, Polypipe worked with project partners to deliver a more durable and cost-effective alternative plastic solution to the original clay and concrete system specified. Following their previous positive experiences with Polypipe, contractor Careys Civil Engineering recommended that the original design specification be changed to a thermoplastic solution incorporating Polysewer and Ridgisewer. Polypipe’s technical experts assisted with any queries about the manufacture and installation of the alternative system, and highlighted the advantages that plastic could deliver over traditional materials.

Polypipe’s plastic systems are able to offer increased health and safety on site, as thanks to being lighter in weight than concrete, they are easier and quicker to install. Made of long-life PVCu, the structured wall pipes offer ring stiffness and strength, while ensuring flexibility to allow for ground movement and differential settlement. Polypipe’s plastic products can be manufactured to exact specifications for each individual project, and delivered at the time they are required, reducing installation and labour time on site.

The plastic solution for the Graven Hill project was successfully adopted by the local water authority, with the final design showcasing Polypipe’s water management product range. The solution included a system for foul water management using over 2,250m of Polypipe’s Polysewer and 330m of Ridgisewer PVCu structured wall pipes, along with the necessary associated bends and fittings required to fit the pipe runs.

To capture, store and control surface water run-off, over 220m of Ridgistorm-XL large diameter pipes were supplied in a stiffness class of SN2 to suit the site’s ground conditions, together with two tanks manufactured using Polystorm-R cells. Polypipe’s Polystorm-R cells boast a 95 per cent void ratio, with a load bearing capacity of up to 61 tonnes per square metre, making them ideally suited for trafficked and loaded applications at greater depths. The two tanks will provide over 336m³ of water storage, meaning that the Graven Hill site will have the capacity to store and manage excess water in the event of extreme weather events, ensuring flood resilience.

Mick McCaul, Construction Manager at Contractor Careys Civil Engineering, says,

“We have worked on numerous projects with Polypipe and have remained impressed with their high level of customer service and the quality of their range of products. We recommended that the original specification for the Graven Hill site be changed to a thermoplastic solution, as we knew that it would be safer, easier and quicker for our groundworkers to install, while offering the robust infrastructure required for this large-scale project.”

Rosie Cheetham, Marketing Manager at Polypipe Civils, says,

“We were pleased to be selected by Careys Civil Engineering to provide an alternative solution for the Graven Hill site, thanks to the contractor’s prior positive experiences using our thermoplastic piping products. We offered consistent communication and excellent client service throughout, to ensure that all technical queries were answered and specification requirements met.”

“The final design incorporated products from across Polypipe’s water management range and highlighted how plastic can offer a cost-effective, durable alternative that can still meet approval for adoption criteria. The system using Polysewer, Ridgisewer, Ridgistorm-XL and Polystorm products forms a vital part of the foundation infrastructure for this innovative housing site, and will ensure efficient water management and resilience in the face of extreme weather events for years to come.”