The ageing Windermere House and Thirlmere House tower blocks in Birmingham were still using original cast iron pipeworkfor drainage. But parts of this system had become brittle, leading to numerous leaks and in one block in particular, complete failure of the waste pipe. As a result, the concrete floor slabs in most flats had become damp and damaged. This meant that a replacement was urgently needed to ensure the comfort of residents, a job that initially seemed straightforward given both blocks appeared very similar in layout. However, as the installation team moved in to replace the failing pipework at Windermere House, they discovered an additional stack serving the ground floor apartments, which had not been on any plans. With tenants in situ, some elderly and vulnerable, excavating through the floors of apartments on this level to uncover where this stack ran wasn’t an option. Ryan Callister, project supervisor for  Legionella & Fire Safe Services explains: “Residents can’t use the facilities in their flats whilst we are carrying out replacement, so being able to complete stack installation safely, quickly, and efficiently in these tower blocks is essential. “In older buildings like these where you’re putting in new pipework, it’s challenging as there can be outdated fittings and connection sizes, as well as varying layouts, as people add and change things over the years. For this project, we had the original drawings, but we can often only spot modifications once plans have been set and we’re on-site starting work. “We needed a solution that would provide the right quality and durability, but within a really tight timeframe.” A new bespoke section was quickly designed and manufactured in HDPE by the Advantage team at Polypipe Services The Terrain FUZE drainage stacks are lightweight and easy to install with temporary mechanical connections at the top and bottom; these were made live quickly, minimising disruption, which was essential so the residents could once again use their facilities and also minimise mould from the cast iron system leaks.