Pedestrian Paver HydroSTON 50

The principal effect of slope on any permeable pavement is the degree of infiltration of rain and stormwater. The greater the slope, the faster will water move over the pavement hindering infiltration through the pavement. This applies particularly, of course, to periods of heavy rainfall.

Unlike permeable pavers that rely for infiltration on gaps in the paver structure, HydroSTON is porous and free draining across the full face and body of the paver. While HydroSTON functions best in terms of permeability when laid at zero gradient, HydroSTON permeable pavements may be constructed on slopes up to at least 7% (gradient of approx 1:14) without adverse effect on infiltration performance. Nonetheless, a number of HydroSTON driveways have been installed in high gradient situations and appear to be effectively capturing and infiltrating rainfall. Light rainfall should be infiltrated regardless of slope.

Another issue with steep driveways is abrasion. HydroSTON is manufactured using a special formulation of 5mm virgin basalt aggregate, sand and cement to create interconnected voids through which water will flow. It is a very strong and durable product. When installed on steep driveways, the pavement surface may be affected over time to abrasion from braking or acceleration. Should extreme damage occur, however, the segmental paving units can be easily lifted and turned over or replaced with new units.

Gap joints are not required with HydroSTON 50 pavers, which are intended for pedestrian only purposes. Joints are not required because the loading on footpaths, courtyards etc is minimal and HydroSTON 50 pavers are dimensionally exact.

HydroSTON 80 vehicle pavements intended for light vehicles eg residential driveways, carparks and parking spaces are normally laid without gap joints.

When HydroSTON 80 vehicle pavements are to be subject to heavy loadings eg semi-trailers, fire engines or garbage trucks, pavers should be laid with 4mm av. joints to ensure lock up of the pavement and provide flexibility of movement of individual pavers under load. Joints should be filled and compacted with 1-3mm low fines crushed rock.

Please contact HydroCon to find out about a HydroSTON site near you.

Please contact HydroCon to organise a quote.

HydroSTON 80 (4.4kg) and HydroSTON 50 Block (1.9kg) pavers can be sent by Australia Post free of charge.

Large format pavers – HydroSTON 50 Flag (9kg) and HydroSTON 50 Flag XL (15kg) – may be able to be collected, subject to availability of sample stocks, from HydroCon’s Waterloo office or Chippendale sample store (near Central Station, Sydney). Alternatively, large format pavers can be delivered by courier and charged at cost.

Standard colour samples are Light Grey and Charcoal. Please contact HydroCon to organise a sample.

There appear to be no specific requirements for permeable pavers in the National Construction Code (NCC) or Australian Standards. Indeed, there is no process by which a product is ‘approved’ for a particular function, reliance being placed on compliance with relevant Standard provisions.

Australian Standard AS1428.1.2009 covers general technical requirements for Design for Access and Mobility. Because AS1428.1 is referenced in the BCA and in the Disability (Access to Premises – Buildings) Standards 2010, compliance with its provisions satisfies compliance with the BCA.

The most relevant provision for segmental pavers in AS1428.1 appears to be Section 12: Surface of a continuous path of travel “All continuous accessible paths of travel are required to have a slip resistant surface, with a texture that is traversable by a wheelchair”.

HydroSTON pavers are dimensionally exact and are normally laid butted together without gap joints. As indicated in the Specification section above, HydroSTON 80 vehicle pavers (206 x 136 x 80 mm), HydroSTON 50 Block (200 x 100 x 50 mm) and HydroSTON 50 Flag XL (400 x 400 x 50 mm) have 4 mm bevels on all four edges of the upper surface, while HydroSTON 50 Flag (300 x 300 x 50 mm) has 5 mm bevels. HydroSTON has the highest P5 slip resistance rating.

Note 3 of Section 12 states that “paving bricks with bevelled edges or chamfered rises greater than 3 mm . . . . are considered not traversable by a wheelchair”. If a P5 slip resistance rating, no gap joint, minimal difference in bevel rise, and an easily tranversable surface texture is deemed not to fully satisfy wheelchair tranversability requirements, HydroSTON can be laid with the underside upwards, thus creating a bevel free, continuous path of travel.

Notwithstanding specified bevel width, research in the US on wheelchair compatible pavers finds that wheelchair vibrations are lowest when pavers having a bevel width of 6 mm or less are installed in a 90 degree herringbone pattern in the direction of wheelchair travel. The research affirms the acceptability of segmental paving in designing for access and mobility.

HydroCon considers that HydroSTON permeable pavers can be laid to comply with Section 12 but notes that pavement design and construction is also critical to compliance. In view of this, HydroSTON pavements should be installed, wherever possible, by contractors recommended by HydroCon.