A 3 000-m2 roof for a 
 forensic science lab-
 oratory, which is currently being built for the Department of Public Works, in Plattekloof, Parow, Cape Town, and set for completion next year, is being covered in Rheinzink titanium zinc and will be one of the largest expanses of its kind in South Africa, reports distributor Rheinzink South Africa.

Rheinzink, an alloy consist-ing of 99,995% of high-purity zinc and precisely defined amounts of copper and titan-ium, is increasingly being used by the South African con-struction industry for roofing 
and cladding since it is highly 
corrosion resistant inland, as well as in marine environ-ments, the company states.

The bowl-type structure design requires that each Rheinzink sheet be tapered to accommodate the shape of the roof, says Rheinzink business manager Stephen Wilkinson.

The panels are fixed to the 
shutterply subroof with fixed clips and sliding clips by roofing contractor Rohde Roofing, allowing the roof to expand and contract to the natural temperature changes during the day.

Wilkinson says that, besides blending into any architectural environment, Rheinzink carries a 30-year material guarantee.

It can preserve its properties and appearance over a service life of 80 years to 120 years, even in harsh marine environments, he says.

After a period of natural weathering, the Rheinzink bright-rolled material takes on a pleasant blue-grey patina, a protective layer of zinc carbonate, and does not need paint, surface protection, maintenance or cleaning.

The formation of the patina may occur after four months to three years, depending on the aggressiveness of the environment.

The colour composition of the patina depends on the location of the project.

The forensic science labor-atory, designed by Forensic Laboratory Architects Con-sortium, is being built by con-struction group LTA-Grinaker and is due for completion in July 2011.