The convenience and performance of PermCalc, Brett Landscaping’s design tool for permeable paving, has been instrumental in the specification of Brett Omega Flow as part of a sustainable drainage solution (SuDS) for a new build project in East Sussex.
Carrington Place in Hailsham comprises nine two-bed residential properties, developed by The Park Lane Group with the support of consulting engineers JMLA Ltd.
The site offered limited soakage; as a result, an effective method of sustainable drainage was essential to match greenfield run-off rates. JMLA used PermCalc to devise a system to resolve this issue. The solution combines permeable paving with a system of concrete pipes for attenuation and discharge into an on-site stormwater sewer.
“We were given a demonstration of PermCalc by Brett Landscaping, and felt that it offered a robust and intuitive method of formulating a sustainable drainage system,” explained John Loades, Principal of JMLA Ltd.
“The software is a delight to work with, because Brett Landscaping understand the needs of structural engineers and can anticipate the types of problems commonly encountered with a site.”
PermCalc users are taken through a step-by-step process which is based on the current British Standard guidance for designing permeable pavements. This requires them to enter structural and hydraulic data about the proposed site as well as average rainfall, the type of vehicle load the paving must withstand and any known pollutants that will impact upon water quality.
“The software is particularly useful for calculating the level of attenuation and the depth of sub-base required to achieve it,” confirmed John Loades.
Once the drainage designs had been confirmed, 700m2 of Brett Omega Flow 80mm was specified in two colour variants – charcoal and brindle. The paving was installed by contractor AM Smith Groundworks in line with JMLA’s blueprint.
“The success of the Carrington Place project could not have been achieved without effective sustainable drainage,” explains Laurence Hulkes, Construction Management Consultant at The Park Lane Group.
“Thanks to PermCalc, we were able to harness the permeable paving expertise of Brett Landscaping to devise an appropriate solution that has allowed us to build these high-quality properties without compromising on the surrounding hard landscaping of the site.”
JMLA now uses PermCalc on a regular basis to assist with the design of sites where permeable paving is required.
“Despite the continued lack of an agreed national standard for sustainable drainage, many of our clients are opting to meet Level 3 criteria in the Code For Sustainable Homes and want landscaping that complements it,” commented John Loades.
“As a result, PermCalc has become invaluable in assisting with design ideas and specifications, and I believe that we’ll continue to use it for the foreseeable future.”
