Porous asphalt for fast draining car park surface

The client, East Lindsay District Council, planned to build a brand new £7m state of the art Public Sector Hub facility in Horncastle, Lincolnshire to provide office space for the District Council, Boston College, along with Lincolnshire Police and local medical organisations. The project had a strong sustainability ethos and the building would feature the latest technology with air source heating/ cooling systems and solar PV mounted on the roof to reduce the amount of energy required from the National Grid. A sustainable approach was also needed towards the construction of the large 220 space car park required to serve the new building to avoid surface run off and flood risk to the surrounding area.

After discussions, with the architect, Bond Brown, they opted for a sustainable porous asphalt solution, with Tarmac’s ULTIPOROUS binder and surface course selected in the design. Using a modified binder and open aggregate structure, ULTIPOROUS combines excellent drainage characteristics with long term durability. It reduces direct surface water run-off to help meet planning requirements. It also eliminates the problem of both standing water after heavy rain and ice patches that can occur in cold weather conditions and avoids the need to install expensive additional drainage systems, allowing cost savings and a more sustainable construction, quicker project delivery and reduced disruption to clients and end users. 

Around 175 tonnes of ULTIPOROUS 20mm Binder and 100 tonnes of ULTIDRIVE 10 surface course were supplied by Tarmac and successfully installed over a two day period covering around 1000m². The modified binder helped maintain workability and enabled the contractor to achieve the correct level of compaction. The smooth, even finish met the client’s requirement for a safe, low maintenance, all weather surface. Using ULTIPOROUS meant planning conditions and would keep the car park free from standing water, even after heavy rainfall. It also avoided the need for additional costly drainage systems and was far less labour intensive than alternatives like block paving, which helped saved time and cost for main contractor and ultimately the Council.