Thanks to growing populations and the rapid densification of our urban centres, multi-residential developments are fast gaining ground in Australia. Though this has meant exciting, unprecedented growth within the Australian construction sector, it has also brought about several unique challenges, including waterproofing issues. Seemingly minor issues of ineffective waterproofing or inadequate access for maintenance and repair can in fact have serious repercussions. Costly repairs, reduced liveability, and diminished personal value are all major risks, as are structural damage, unsightly surface stains, and the growth of mould and mildew. Unfortunately, many of the problems associated with water leakage only become apparent once the worst of the damage has already occurred. 

This is particularly true in outdoor spaces such as plazas, balconies, and terraces, which have a high degree of exposure to the elements. The installation of paving and decking systems in these outdoor spaces has the potential to damage waterproof membranes during installation and restrict access to these once construction has been completed. As a consequence, reduced accessibility for repairs and maintenance often becomes a problem down the track.

Elevated paving systems address each of these concerns, with their lightweight nature, easy installation, and high degree of access provision making them ideal for outdoor areas. The systems promote proper drainage and help keep the waterproof membrane intact by minimising direct contact with cement, tools, and foot traffic installation. In elevated paving systems, the weight of the pavers alone holds the entire system in place and prevents lateral and vertical movement in the face of external loading. This allows the system to avoid penetrating the waterproof membrane with any mechanical fixings and also circumvents permanent fixing of the pavers, which minimises access to the membrane.

In theory, the weight of the pavers is sufficient to achieve this. In practice, however, the weight of the pavers may prove inadequate to hold elevated paving systems down in high-speed wind conditions. Recent developments have shown that high-speed quartering winds – which blow obliquely to the building’s orientation – may cause a pressure differential that is enough to uplift the pavers. This obviously reduces the integrity of the elevated paving system, and places occupants, pedestrians at street level, and other parts of the structure at risk of injury from wind-borne debris.

There are three main methods for overcoming wind uplift. The first is to increase the relative parapet height or the ratio of the gap between pavers to the height of the spacers (i.e. the component separating the pavers from the waterproof membrane). The second is to provide grates or increased drainage at regular intervals, connecting the waterproof membrane and elevated paving system and eliminating the pressure differential that causes paver uplift. The third option is to use interlocking or strapping systems, which fix pavers temporarily and securely in place without impeding access to the waterproofing membrane.

VersiJack CPR, a wind uplift concealed paver retainer from landscape engineering experts Elmich, avails of the third mechanism, providing a secure, means of affixing pavers to an elevated paving system. Compact, discreet, and highly effective, VersiJack CPR is designed to attach to any Elmich pedestal and provide high wind uplift resistance for elevated roof pavers. The system is totally discreet and invisible, whilst still providing access to the waterproofing membrane if required. There are no exposed components that could be considered trip hazards. 

Like any interlocking or strapping system, the VersiJack CPR system cannot guarantee absolute wind uplift resistance. In order to follow best practice for preventing wind uplift, architects and specifiers should ensure that all variables of the site conditions that may impact the effectiveness of the system are taken into consideration. Wind engineers can be engaged for these purposes and are able to calculate if wind pressure needs to be reduced through alternative means. 

Since its establishment in 1985, Elmich has earned a reputation as a leading provider of cutting edge, sustainable solutions for urban landscaping, drainage, and storm water management. Around the world, the Elmich brand has become synonymous with quality, durability, and environmental sensitivity and is instantly recognised by its passionate, comprehensive customer service.

Learn more about VersiJack CPR and Elmich at https://elmich.com.au/products/versijack/ or by watching this video.