A sustainable, BBA accredited asphalt SDS system that also contributes to BREEAM – Car park, Portsmouth

Pompey Car Park, Portsmouth





Tarmac Contracting

Location type

Car park


September 2002

The challenge

HGP architects developed the largest B&Q store in the country at the Pompey centre, Portsmouth. The store includes 120,000 sq ft of retail sales area and a 30,000 sq ft garden centre, with the car park being 20,000m2. The site is built close to the sea and the contractor wanted to construct the car park using a product to help with surface water management and run-off.

Our solution

The ULTISuDS design incorporated a bespoke infiltration system using a granular reservoir base and the hydraulic performance of each asphalt layer was tested to assess compliance before laying the next. The Transport Research Laboratory (TRL) assessed the pavement condition using a falling weight deflectograph (FWD) prior to the official opening. The results showed that there was consistency throughout the site in terms of both stiffness and deflection and the structure was considered suitable for the purpose that it was designed for. Because positive drainage was not necessary there was an overall significant cost saving to the main contractor.

Results and benefits

The ULTISuDS system supports rain management by working with nature. It is designed to capture rain and surface water before either storing it for recycling, releasing it immediately into the sub-grade or performing a controlled release into the existing drainage. Having removed the need for any additional drainage systems, it made the car park projects much more cost effective.

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Additional info

Proven Performance

Using the latest porous asphalt technology and a modified binder, the open aggregate structure allows effective surface water runoff drainage and maintains long term durability on a wide range of SuDS applications.

Outstanding performance

ULTISuDS Achieves a Hydraulic Conductivity rating at installation of 5000mm/hr far exceeding the worst recorded UK rainfall of 100mm/hr.

Enhanced compliance

As part of a sustainable drainage system pavement, ULTISuDS meets the requirements of planning regulations and the Code for Sustainable Homes.

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