Case Study - Reroofing of St Georges Cathedral, Cape Town South AFrica
Clay Roof Tile
A mixed blend of Dreadnought plum red 65%, Brown Antique 20% and Country Brown 15%
Lucien Le Grange
Specialist Heritage advisors :
Rennie Scurr Adendorff Architects
St George’s Cathedral in Cape Town is the oldest cathedral in southern Africa, built by Sir Herbert Baker in the Victorian era. The foundation stone was laid in 1901 by the future King George V. However, it has even greater acclaim as a symbol of democracy in South Africa and for its role in the resistance against apartheid having welcomed people of all races throughout the apartheid era. It was from the front steps of St George's Cathedral, or the “Peoples Cathedral” as it has become known, that Desmond Tutu led numerous marches and campaigns for the formal ending of apartheid.
Despite its historic importance as well as its status as a Provincial Heritage Site which provides protection under the South African Heritage Law, the cathedral roof had been lacking in regular maintenance and it became clear that a complete overhaul was required. Lucien Le Grange was appointed as the project architect but John Rennie of Rennie Scurr Adendorff Architects, Specialist Heritage advisors was consulted early on before the necessary funds had been raised. John devised a special timber walkway all the way around the main 54º roof to serve as a tile catching balustrade to protect the public walkways from falling tiles, whilst the renovation project gathered the required funding to go ahead. He felt this structure might also provide a visual focus to the fund raising and moreover it would provide access to the roof as a form of scaffolding.
John found no less than 8 different clay tiles were used on the original build which took place in stages between 1901 and 1965. Some of the tiles showed no brand names but he did find Perfecta and Sovereign Broseley tiles which were both made in the UK from Etruria marl clay but are no longer manufactured. John set out to find a similar traditional clay tile that would suit the historic status of the building.
He found Dreadnought Tiles (also made from Etruria marl) on the internet, and they had been used to renovate the Governor’s House in New Zealand also replacing old Perfecta tiles, made by Thomas Peake Ltd. Unlike most clay tiles manufactured today, Dreadnought's roof tiles are naturally coloured by skilful control of the firing process rather than by using applied surface stains and pigments. This process generates a truly traditional product with the same character and appearance of tiles made over 100 years ago. John ordered samples and decided that Dreadnought’s Plum Red provided the best match and that blending in some Brown Antique and Country Brown tiles would add more tonal variety to this large roof. In the UK, tiles are tested for frost resistance which is not such an issue in the South African climate. However, wind and rain can be more severe and John was keen to check the water absorption of the tiles to ensure that their weight when wet would not cause issues for this old building. He saturated the tiles himself, weighing them when both dry and wet and he found that they only gained about 1-2% in weight when wet and would therefore be ideal for the job.
Securing the funding for the project however was difficult. An urgent appeal was made to the public asking for their support in the project by donating the cost of the roof tiles but finally some funding was made available via the South African State Lottery though unfortunately it would only cover part of the roof. Leith Roofing have carried out the work so far, using 80,000 Dreadnought Tiles in a mix of 66% Plum Red, 20% Brown Antique and 14% Country Brown and they did an excellent job of mixing the tiles on the roof. Leith Roofing Director, Andrew Gilbey explains, “everybody who has seen the roof has commented on how wonderful it looks. Our new President was at the Cathedral for his inauguration and even he commented on how nice the new roof looks.” It is hoped that further funding will soon be secured to complete this conservation project.