Upmarket residence constructed in only three days, using tilt-up concrete panels.
The remarkable, upmarket Van Eck house in Durban was built using the tilt-up construction approach, showcasing the adaptability of the system in all forms of construction. Except for its glass and Rheinzink roof structure, the entire house was built with concrete.
Tilt-up construction involves the onsite casting of a variety of large precast concrete elements in size, finishes and shapes, which is then lifted into their designed positions by means of a mobile crane. These elements are then held in place by means of braces until they are connected into a unified structure. Because the panels are cast in an open face manner, the surface is power-floated, which eliminates the need for plastering.
According to Charles van Eck from Tilt Up Technologies, wall panel elements weighing in excess of 64 tons with heights of up to 26m have already successfully been constructed and positioned in South Africa.
Van Eck introduced the local construction industry to the tilt-up building method in the early 80s, with the first ever South African tilt-up project being completed in Durban in 1983. Today, the technology is used all over the country. With more than 60 years in the building industry, this residential project is a personal milestone for Van Eck and a celebration of what can be achieved by taking the tilt-up approach.
Creating the curve
Built on a spectacular 12ha site overlooking a gorge in Everton, Durban, Elphick Proome Architects designed the house in a curve to maximise the magnificent 180° view.
“The fact that we used curved panels, posed no specific challenges,” says Van Eck. “Determining the required radius, the shape was excavated in the ground and a 60mm thick concrete sacrificial casting bed with a power-floated finish was formed to fit the excavated shape, which provided a perfect off-shutter finish on both sides of the panel,” he explains.
The puzzle pieces
Approximately 108 elements went into the building, which took only three days to erect. “The largest of the curved panels used on the project was 15m long, 2,8m high and weighed 16 tons,” Van Eck adds. “Being a house, the panel sizes varied from 1m to 15m wide.”
Building the tilt-up way, the thickness of the panels is normally determined by the structural engineer, depending on what structural work the panels will be required to do. In most cases, the panels function as structural elements instead of just being mere cladding.
Quarts strip finishes
Adding another modern, stylish touch, the architects specified quarts strip wall finishes for some of the external panels as well as a number of the 4m high by 3m wide retaining wall panels.
“To achieve this, the quarts stone simply had to be laid in the required pattern within the panel edge forming, after which the concrete was cast on top of the quarts, which in turn held the quarts stone in position. Once cured, the panel was lifted in the normal manner by crane, resulting in the required finish,” Van Eck explains. “This method was quicker and much more cost-effective compared to the conventional way of doing quarts strip walling.”
Further contributing to time and cost savings, is the fact that the face of the wall panels doesn’t have to be plastered due to open face casting which is power-floated, strip footings is eliminated since the panels are in effect beams that only need to be supported at both ends.
“Tilt-up construction is not a highly technical method of construction,” says Van Eck. “It simply does what has always been done, in a cost-effective, simplified way. As is the case in conventional construction, attention to detail is important – ignore this rule and as with anything in life, you will pay the price. But any contractor worth his salt will have no difficulty in building the tilt-up way,” he concludes.
Tilt Up Technologies (Pty) Ltd
Tel: 031 7670077
The project in numbers:
– 12ha site.
– 180° view.
– 108 elements.
– Panel widths from 1m-15m.
– Three days to build.