Client: Southern Water
Architect: Montgomery Watson Harza (MWH)
Main contractor: 4Delivery Consortium
Installation contractor: Prater Ltd
Building Systems UK products: RoofDek D100; Trisobuild® C19 Profile; Double-sided Colorcoat HPS200 Ultra®

Peacehaven Wastewater Treatment Works, Southern Water’s £300m, state of the art wastewater treatment works services the Brighton and Hove catchment area. Located at Lower Hoddern Farm in Peacehaven, East Sussex, UK, the works treats 95 million litres of wastewater a day. It features the UK’s largest green roof of its kind, covering an area of almost two and a half football pitches.

The challenge

“Due to the level of investment that had already been made into the project throughout the ten years previous we needed a cost effective yet environmentally sound solution,” said Phil Risbridger, Project Director of the 4D consortium, comprising of Costain, Veolia Water and MWH.

“The two don’t tend to go hand in hand but Prater proposed a new system whereby we would build greenery onto a Building Systems UK (A Tata Steel Enterprise) roof decking-based single ply roof, providing the cost and time benefits we needed, while staying true to the visual challenge of Southern Water’s environmental improvement scheme.”

The biggest challenge on-site was logistics in terms of transferring the thousands of tonnes of substrate onto the roof and covering the complete area using mobile tower cranes. To overcome this issue, a series of conveyor belts were used to transport the volume of material, which was then raked to follow the curve of the building.

The solution

Designed to accommodate the additional loadings imposed by green roof construction, RoofDek D100 features a 700mm cover width and a 233.3mm pitch that provides a very strong deck and offers excellent insulation support. Its lightweight construction also minimises the load on the building structure.

Prater provided a total envelope solution for the project, including walls featuring the Trisobuild® C19 profile in Olive Green 0.7mm double-sided Colorcoat HPS200 Ultra® in single and double skin configurations. Double-sided Colorcoat HPS200 Ultra® was ideal for the demanding internal environment at Peacehaven Wastewater Treatment Works, where the same unique formulation topcoat and corrosion-resistant primer applied to the reverse side provides a robust barrier on both sides of the steel substrate.