A Commonly Owned Access Lot (COAL) is often needed for urban projects where subdivision or infill development is undertaken. COALs can, in some situations, contribute a large amount of impervious area to a project. Runoff from this area could require treatment and attenuation depending on the planning requirements of the project.
This project on Banks Road had severe limitations with stormwater connections. The design philosophy adopted by ACH Consulting was to reduce the permeable area of this site as much as possible and provide all treatment at source. A solution was needed for a permeable common access way, that would be hard-wearing to support vehicle access and meet the Auckland Council accessway standard.
Stormwater360 Grasscrete™ was chosen as it ticked all the boxes. The 150mm reinforced concrete slab met the Auckland Council requirements and minimised runoff from the entire COAL. Using a cast in-situ solution minimised any issues with differential settling and turning loads on the pavement, is load-bearing up to 40 tonnes of gross vehicle weight, and has a high drainage capacity. Star Homes installed the product and completed the subdivision, receiving council sign off.
