An effective method of sustainable drainage was required by consulting engineers JMLA for Carrington Place in Halisham to match greenfield run-off rates as the area offered limited soakage.

PermCal software provides users with a step-by-step process based on the current British Standard guidance for designing permeable pavements, comprising a feature enabling the input and recording of structural and hydraulic data about the site, average rainfall, type of vehicle suitable for the work and any pollutants that will impact water quality.

The software also provides help to engineers wanting to calculate the attenuation and the depth of sub base required to fulfil requirements, assisting with the design of sites where permeable paving is needed.

Following the confirmation of the drainage designs, 700m2 of Brett Omega Flow 80mm was ordered in charcoal and brindle colours, with the paving installed by contractor AM Smith Groundworks.

PermCal provides assistance for clients wanting to design and specify systems that meet the Level 3 criteria in the Code for Sustainable Homes document.