Identifying what factors contribute to the rapid uptake of suspended paving by the flooring industry.
It can be quite a challenge to convert a dull bitumen-coated flat roof or terrace into an attractive paved surface without making use of grout or any other form of binding agent. However, a possible solution can be found in suspended paving – a process which utilises concrete flagstone pavers without using any binding agent.
Unlike conventional paving or tiling on a concrete surface in which the pavers or tiles are attached directly onto a concrete base layer using grout or some other binding agent to create an impervious watertight surface, suspended paving entails pavers that are mounted on small polythene sandbags without the use of any adhesive or binding agent. The only requirement for keeping the pavers in place is their weight. In addition, they are laid 10-12mm apart to create a water permeable surface.
These and other numerous benefits explain why some of the country’s leading architectural practices are turning to suspended paving. In fact, this process has already been used on some major construction projects using pavers supplied by Cape-based Concrete Manufacturers Association NPC (CMA) member, Revelstone.
Recent projects include Cape Peninsula-based projects such as Liberty Life’s headquarter premises in Century City, Bloemhof in Tyger Valley, Wembley Square in Gardens and some student residences in Stellenbosch. Suspended paving has also been used at Dainfern Square in Johannesburg and Liberty Life’s Umhlanga offices in KwaZulu-Natal, among other high-profile projects.
According to Johnny Schwartz, a partner of Louis Karol Architects who is considered as a suspended paving pioneer, the process offers some distinct advantages over conventional roof-top or terrace paving.
“Firstly, it allows for the creation of a level paved surface on a base which is sloped for drainage purposes,” he explains. “Flat surfaces are achieved by altering the thickness of the supporting sandbags to compensate for the slope. Secondly, because the paved surface is permeable, there is no water pooling, even during the heaviest of storms. This means that as soon as the rain has abated, the surface can be walked on without worrying about wet feet.”
Louis goes on to say that another major advantage is the fact that the paved surface creates a protective layer, which shields the waterproofing on the base layer from the sun’s UV-rays and other forms of possible damage. However, in the event that the base layer does require some routine or other maintenance work, it is easily achieved by simply lifting the pavers and then re-inserting them once the job is completed.
“Compare this with the expense and inconvenience of lifting and replacing pavers which have been grouted to the base layer,” states Louis. “Moreover, no expansion joints are needed with suspended paving and there is no chance that the pavers will crack or lift due to wind or earth-induced movement.”
Revelstone director, Alex Cyprianos, says that suspended paving is generally used in low-traffic areas such as concrete roofs, balconies and terraces.
“The pavers tend to be large, averaging 600 mm² and 55mm thick,” he says. “We produce a wet-cast flagstone paver that is steel-reinforced, and we can also make up special shapes to accommodate curved borders.”
The sandbags used in suspended paving are filled with a mixture of sand and cement that hardens once the laying process has been completed. Over time the polythene outer casing will deteriorate, leaving a hard and durable concrete core, resulting in an installation that is flawlessly functional for several years to come.