Is Natural Paving a permeable paving surface?

Yes, Natural Paving is a permeable paving surface. It has the permeability and maintainability required to comply with the Auckland Council guidelines. The paved surface, however, is just one of nine elements that contribute to a compliant pavement. On our website you can see a diagram and details of the other eight elements. This is based on the Auckland Council website (click this link to read the pdf version of permeable pavement guidelines specs), The permeable pavement guidelines idea is to intercept runoff and hold it while it infiltrates into the ground, or, its entry into the storm water system is delayed. Where the sub-grade is poor draining soils, in high groundwater areas, or in structurally sensitive soils, the sub-grade is lined with an impermeable membrane and provision is made to collect the infiltrated water and pipe it into the storm water system. Runoff is also intended to be purified of sediment and oil that drips on pavements by the swale action of the base layer. It is also intended that the permeability of the surface can be reinstated if it becomes blocked. Natural Paving filters out sediment so the water entering the reservoir is quite clean. If it is required after a time, Natural Paving can be restored to its original condition by tipping the pebbles out of the mats, washing them and relaying them with clean pebbles. The rain that permeates through the surface needs to be collected and held in a reservoir that has the capacity required by the approving authorities. This reservoir is typically the base course in a permeable pavement. The base course has a strict grading (the distribution of sizes of the stones in the aggregate) to ensure there are air voids after compaction. Air voids weaken base course, so it is needs to be made from tough gravel. The voids are needed to contain the water from the rain. The base course must be from a crushed aggregate to have good shear strength. If the pavement has a clay sub-grade, the council requires an impermeable liner so the clay is not softened by water, and consequently squeeze into the voids. There also needs to be a facility to collect the infiltrated water, and pipe it into the storm water system. The pavement also needs to have strong side support in the ground around the perimeter of the pavement because loads on the surface push sideways within the base course much more than common ‘well graded’ base courses. This requirement is number eight in the specification. Then there is also the environmental considerations of the likely traffic volumes, adjacent land profile and how much run-off it spills onto the pavement, the presence of deciduous trees, the long term maintenance requirements, and the owners acceptance of test and maintenance covenants that the council will apply. I hope you can see that there are many elements that will be considered in the approval of a permeable pavement, and unless they are all present the pavement will not function as intended. Consequently the pavement is assessed as a system for a particular application, and approval of a pavement does not imply another pavement in a different location will also be approved. Natural Paving is an ideal, highly permeable and easily maintainable surface for a permeable pavement. It is a better surface than any other surface because the geotextile bonded to the plastic matrix filters sediment out of the rain, and it is relatively easy to reinstate the original permeability should the surface become clogged. I will be very happy to work with your engineers or landscape professionals to work out the details for the successful application for a permeable pavement.