Sika was called in to provide the solutions when repairs to Durban’s North Ridge Reservoir ran into deep water. The rehabilitation of reservoirs is always challenging, requiring speciality products that keep them watertight against both ingress and leakage of water. The waterproofing layer cannot contaminate the drinking water nor affect its taste and odour, and it must inhibit the growth of fungi or bacteria. It should also be easy to inspect, clean and disinfect, and be resistant to damage from drinking water.

The Sika range of waterproofing products meets all of these specifications, and more, by providing liquid membranes that also bridge cracks and accomodate movement in the substrate.

The North Ridge Reservoir, however, required more than just excellent waterproofing products. The project, which was undertaken for the eThekwini Municipality by Erbacon Construction, ran into problems when it was noted that the existing internal concrete walls were too soft to hold the waterproof coating , SikaLastic-150 , specified by Graham Moore of PDNA.

The substrate had to be broken back sufficiently, by pressure blasting, to reach concrete with enough strength to hold the waterproof coatings. Sika is considered the global industry leader in concrete repair and protection and many years of research and development plus decades of practical experience has enabled Sika to provide systems to restore and rehabilitate concrete and masonry structures that have deteriorated due to corrosion and water infiltration.

Sika has long believed that one of the keys to ensuring repairs are both durable and long lasting is to fix existing damage and protect against future damage.

Sika MonoTop-610, a one component polymer modified bonding slurry and anti corrosion primer was used as a bonding slurry onto the concrete for the Sika Monotop repair mortars. Sika MonoTop-612, a one component polymer modified repair mortar containing silica fume and synthetic reinforcement fibres, and Sika MonoTop-615 HB, a high build polymer modified repair and reprofiling mortar, were then applied. Sika Rep LW, Sika’s non-sag patching and repair mortar for cosmetic or structural repairs of deteriorated internal or external concrete surfaces was used for internal concrete repairs to the soffit.

With repair work comprehensively taken care of, the structure was now ready for the application of Sika’s speciality waterproofing and protection products. A universal waterproofer and bonding agent, Sika Cemflex, was used on the roof of the reservoir, while SikaLastic-150, a highly elastic cement based waterproofing coating was chosen for the internal walls. SikaLastic-150 is a fibre-reinforced product capable of accomodating substrate flexural strains combined with excellent crack bridging capabilities, even on existent cracks or cracks that might open after the product application.

Thanks to Sika’s commitment to finding innovative solutions designed to fulfill basic human needs, the people of Durban will be drinking safe, uncontaminated water for many years to come.