Recently Sika has played an important role in the repair and refurbishment of Cape Town’s famous Civic Centre. Built in 1978, this well-known landmark in the city centre comprises two blocks; the low-rise Podium Block, and the 98m, 26 storey, Tower Block. Seven years ago concrete repairs and rehabilitation were carried out on the Civic Centre as Phase 1 of its facelift. However due to lack of funds at the time, Phase 2, the waterproofing and coating of the project, was delayed until 2011.

By the time Phase 2 commenced, concrete repairs, joint sealing and cover enhancing were also necessary. This portion of the project was awarded to GVK Siya Zama Building Contractors, specialists in landmark, high profile buildings in South Africa. Two top quality Sika products were specified for those areas displaying deteriorated concrete; Sika MonoTop-612, a high strength repair mortar containing synthetic fibre reinforcement, and SikaMonoTop-615 HB, a high build, one-component reprofiling mortar. Both products contain silica fume, are ideally suited for overhead and vertical surfaces and display excellent workability characteristics, as well as being sprayable by the wet spray method. A third product used in this application was Sika Rep LW, a non-sag, cement-based, multi-purpose patching and repair mortar.

SikaTop-Armatec-110 EpoCem, a cement-based, epoxy-modified bonding agent was applied as a bonding medium for the repair mortars to the old concrete. Containing corrosion inhibitors, this excellent wet to dry adhesive provides a high degree of mechanical strength and may be spray applied. Grouting was done using SikaGrout-212, a fluid, expansive cementitious grout, providing rapid strength development and high final strengths.

Failed joints were replaced with Sikaflex AT-Façade, a moisture-curing, elastic sealant based on silane terminated polymers. Especially suited for movement and connection joints, it offers excellent weatherability with the highest UV resistance. Further joint-sealing was achieved by using Sikaflex-11 FC+, a multi-purpose adhesive and elastic sealant based on polyurethane, which is suitable for indoor and outdoor applications on vertical and horizontal joints.

The main expansion joints in the buildings were sealed with Sika’s innovative Sikadur-Combiflex SG bandage system which consists of a modified flexible polyolefin (FPO) waterproofing tape and Sikadur-31 CF Normal, a two-part, thixotropic adhesive based on a combination of epoxy resins and special fillers.

KFD Wilkinson Consulting Engineers, the same company responsible for Phase 1, awarded the Phase 2 waterproofing contract to Haefele Waterproofing, who specified several of Sika’s outstanding products for this portion of the project. Sika BlackSeal T-140 PG (0o C) was applied to the 4,000m2 rooftop area as an intermediate layer and followed by a layer of Sika BlackSeal T-140 SG (0oC). These products are 4mm thick, torch-on waterproofing membranes that are flexible to 0oC and are based on APP (atactic polypropylene) modified bitumen, reinforced with polyester non-woven fabric. The second layer (SG) provides a sand broadcast surface. The rooftop area was then completed with a protective layer of UV resistant Sika BlackSeal-Silvercoat, a solvent-based, aluminium-pigmented, bitumen coating that may be applied by brush, roller or airless spray. As a loose-lay protective layer for Bituthene 3000, Sika BlackSeal T-130 PG, a 3mm thick waterproofing membrane, was applied to the 10000m2 area of the Podium block.

Parapets and upstand terminations were waterproofed with Sikalastic-150, a two-part, fibre-reinforced coating that, due to its high degree of elasticity, may be applied to structures subject to thermal movement and vibration. This easy to apply product with its excellent crack bridging capabilities provides optimum adhesion onto almost any substrate. Further waterproofing and damp-proofing of the buildings were achieved by applications of SikaTop Seal-107 ZA, a two-part, mortar slurry comprising a liquid polymer and a cement based mix incorporating special admixtures.

Coating of the main structure of the Civic Centre was carried out by Marmoran using customized natural protection wall coating systems.

One of the challenges that presented itself prior to commencement of repairs and renovations, was that the entire sculpture in the main courtyard had to be dissembled and subsequently reassembled once all work in that area was completed. This was carried out with extreme precision and looks as though it was never touched.

This significant project, involving the application of over a dozen of Sika’s high performance products, has been in progress for the past twelve months, and is scheduled for completion towards the end of 2012, whereupon the City of Cape Town will undoubtedly feel proud of its famous, refurbished Civic Centre.