First things to think about:

What is the natural underlying site material (subgrade) – is it clay or sand or something in between?

How permeable is the subgrade? If clay, probably not at all, so drainage will need to be provided; if sandy, then likely to be highly permeable – water will seep quickly into the ground.

What will the driveway be used for? Cars or heavier vehicles? The driveway, and substructure in particular ie that part of the pavement between the permeable pavers / bedding layer and the subgrade, needs to be designed for likely loads.

Will the driveway be used to temporarily store water ie temporarily retain stormwater runoff or for collecting stormwater for onsite use? A sub-base may need to be added to the base course to increase water storage capacity. But, increasing the depth of the substructure may not be advisable if the driveway is to carry heavy vehicles.

Is or will the driveway be on a slope? HydroSTON driveways work best, ie infiltrate water better, when slopes are less than 7% (gradient of approx 1:14). The greater the slope, the faster water flows over the pavement when rainfall is heavy. Slope, however, is not necessarily a limiting factor.

Which pavers to use ?

HydroSTON 80 vehicle pavers should be used for driveways. HydroSTON 80 (206 x 136 x 80 mm) is specially dimensioned for strength but can also be used for footpaths.

HydroSTON 50 pedestrian pavers (200 x 100 x 50 mm and 300 x 300 x 50 mm) must only be used for footpaths, courtyards etc.

What colours are available ?

Standard colours are Natural (light grey) and Charcoal.

HydroSTON 80, however, can be manufactured to customer colour preference. Due to tyre abrasion, some surface colour may wear off over time exposing the natural colour of the basalt aggregate from which HydroSTON is made. The resultant mottling effect may enhance the pavement’s aesthetic appeal.

Other things to consider

Edge (perimeter) restraints are essential to prevent the pavement spreading over time. Contractors can generally advise on the most suitable restraints for a particular driveway. Options include existing walls or other brick / concrete structures, and specially created concrete haunches with or without kerb. The most common approach is to lay HydroSTON 80 pavers at 90 degrees to the perimeter (called ‘headers’), partly mortared to a subsurface haunch or stabilizing slab.

Joint gaps or no gaps? HydroCon normally recommends that HydroSTON vehicle pavements be laid in herringbone pattern with av. 4mm joints filled and compacted with specially graded 1-3mm low fines HydroCon Joint Filler. However, small driveways and residential parking spaces can be laid without gap joints, in which case joint filler is not required.