Completed in Spring 2024, Stockport Interchange was one of the biggest single projects outside of London. Undertaken as part of a two-year-long £90million regeneration project that put sustainability at its centre, the result was a series of paths, cycleways and an elevated two-acre park, located above Stockport’s new bus station and named Viaduct Park, that creates a gateway to the town in Greater Manchester.
“This is a monumental project,” Nicholas Wright, Business Development Director for Specification at Polypipe Civils & Green Urbanisation, said, “it is the first of its kind in the UK – collectively, we’ve been able to deliver a park in a place where there was never one before.
“To do that, we supplied a range of Permavoid products, wicking geotextile and Terrain domed roof outlet and worked with the Environmental Protection Group (EPG) to pull it all together.”
Phil Williams, Director at EPG, said: “When we initially reviewed the designs, we highlighted some concerns around providing the park on the roof, and the ongoing maintenance of said park – particularly in terms of irrigation. The original plans didn’t include any taps to water the plants, and the other big element was that the park was doing no attenuation at all. Essentially, it was just acting as a green roof, with all attenuation taking place beneath the actual bus interchange, underneath the ground floor.
“However, there were a number of limiting factors for that attenuation. For example, going too deep puts you into rock, and going too deep could also lock up the tank when the River Mersey rises during flood events, which is a problem when it needs to discharge. So, the solution here was to work with our partners, and local community to create a plan to develop a blue roof on the park, for which we used the Permavoid product with the patented capillary cones to mimic nature.”
“Different types of Permavoid product were used for this project – we specified Permavoid ², and of course the capillary cones to enable passive irrigation, which was a key element because there’s a need to ensure the park survives over the summer months,” Nicholas added, “and the stronger Permavoid 85 was used too, particularly in areas where there were access points or maintenance vehicles, and also where there may be market stalls in the future so, while passive irrigation was important here, so was the structural strength.”
“Naturally, there were slight changes throughout, and a lot of complexities but, for a project so large, it went smoothly. We’ve had a long track record of working with Polypipe, and it’s always helped us – the same goes for this project. Polypipe CGU have an extremely knowledgeable field team which is a great strength, and it creates added peace of mind, with them being able to act as our eyes and ears on site - it’s a huge help in feeding back both ways,” Phil said.
“This project was undertaken with support from the Environmental Agency – this alone is a testament to the quality of the design and commitment to sustainability, which, from the very outset, was a key element,” Nicholas said.
“As with many of our projects, it’s all about sustainable, resilient development. Part of our contribution to that relates to the use of our Permavoid products. Our Permavoid range is not only renowned for its strength and efficiency in terms of water management, but also for its 100 percent recycled content. Plus, we hold Environmental Product Declarations (EPDs) for the Permavoid range, providing both credibility and transparency on the environmental impact of the products throughout their lifecycles – something that we’re very passionate about, as a business.”
