TarmacDry for Withywood car park

Back

Architects Quattro Design contracted to design a 2,000m2 car park at the Withywood Community Centre.  They chose TarmacDry porous asphalt system to meet the brief's sustainability requirements and minimise the impact to the local environment.

The project resulted in a porous asphalt car park with an in-built weir system.  The weir system forms part of the reservoir layer providing increased storage capacity.  Inlet pipes transfer rainwater from the 2,500m2 roof of the community centre into the porous asphalt layers. 

Why was TarmacDry the solution?

The system comprises an aggregate reservoir made from a specially graded sub-base material that is designed to create the maximum void space in which to store water. TarmacDry's sub-base can accommodate water more than 30% of its own volume, which can be held and then channelled into existing drainage system, or captured for use as grey water. The aggregate sub-base also provides a stable platform on which to construct the required porous asphalt layers. The system has a permeability designed to cope with up to 5,000mm of rain per hour.

As the rainwater drains through the porous reservoir, it is cleansed of impurities like oil and sand, so that it re-enters the drainage system as grey water and can be used without further reatment for applications that do not require potable drinking water. This helps to reduce the demand on primary drinking water supplies, providing an environmentally friendly and cost effective whole life alternative to traditional drainage systems. Because the technology is flexible, if designed into projects at an early stage, TarmacDry porous asphalt system can also be used to provide grey water supplies for domestic use, like toilet flushing and general garden watering.

For details please download the full case study: Withywood Community Centre Car Park, Bristol (pdf, 386kb)
Read more about TarmacDry porous asphalt system

Back