Introducing the finalists Herbert Prins Colosseum Awards. The restoration of the neo-classical facade of the Robert Sobukwe Blockfor the University of the Witwatersrand |Kate Otten Architects

The Central Block or Great Hall was the outcome of an architectural competition for the main buildings of the new campus for the University of the Witwatersrand. Convened in the 1920’s, first prize was awarded to the architect Frank Emley of Emley and Williamson. The project was duly tendered, and Barrow Construction were appointed, and the building completed in 1922.

The fine workmanship evident in the columns and the many different component parts was due to the very capable patternmakers employed by Barrow Construction. The accuracy and sharp edges of the concrete blocks speak to a high degree of excellent craftsmanship.

In 2020 pieces of concrete were falling from the facade onto the Great Hall steps. Closer inspection revealed long term weathering of the precast concrete blocks as the likely cause.

A temporary catch net was installed, but it was not until a substantial scaffold had been erected across the entire temple front facade that the scale and extent of the problem was properly defined. The decorative modillions were found to be significantly spalled and numerous other issues identified that required restoration.

The main contactor AJ Renovatum was appointed who in turn appointed Old World Concrete to make replicas of the modillions - and other items - using latex and glass fibre moulds. A decision was taken to not clean the building with high pressure cleaners as this would have stripped the 100-year-old patina. The facade was however carefully washed by hand with nylon brushes, a mild detergent and water.

The double pitched roof over the temple front was clad with a standing seam copper roof as a permanent and very durable solution. The restoration of the front steps and the floor of the loggia was also attended to.