February 2016 marked the start of an estimated fifteen-month restoration project on one of the largest apartment blocks in the Southern Hemisphere. The site was the T-shaped Bencorrum Towers in Durban’s beachfront precinct, comprising 334 units and housing over a thousand people. Built in the early 1930s, the once well maintained Bencorrum Towers, one sixteen storeys high, the other twenty-three storeys high, had deteriorated to a state of total disrepair. Sika’s Technical Sales Consultant, Mark Duckham, is advising onsite.
With the scope of works, which includes moderate to severe concrete repair, refurbishment and protection; Curasure KZN, a building maintenance consulting company, specified products from Sika’s renowned MonoTop range of ready-to-use mortars. The Ikusasa Group undertook quantity surveying for the project while the application contract was awarded to Coating Worx KZN.
Sika MonoTop-610, a cementitious, polymer-modified, one-component bonding slurry and primer is applied for protection of the reinforced steel. Active corrosion inhibitors in Sika MonoTop-610 meet international standards for corrosion protection while its excellent adhesion to concrete and steel provides high resistance to water and chloride penetration. Sika MonoTop-612 is a cementitious, polymer-modified, low permeability mortar containing silica fume and synthetic fibre reinforcement, and is used as a high strength repair and reprofiling system. Its excellent slump resistance allows for easy application on overhead and vertical surfaces.
For thick layer concrete repairs, Sika MonoTop-615 HB was used. This is a high build, cementitious, polymer-modified, one-component repair and reprofiling mortar containing silica fume and Ferrogard corrosion inhibitors. It displays excellent thixotropic behaviour. For thin layer rendering on horizontal and vertical surfaces, Sika MonoTop-620 was the product of choice. A cementitious pore sealer and levelling mortar containing silica fume, it provides excellent adhesion to mortars and concrete. All Sika MonoTop products are sprayable by the wet spray method and provide several advantages including adjustable consistencies, excellent workability characteristics and good mechanical strengths.
As with all high rise buildings undergoing external renovations in densely populated areas, public safety takes priority. Since Bencorrum Towers is situated on an extremely busy street, a mere stone’s throw from Durban’s famous beachfront, and due to its level of dilapidation, falling debris is of major concern. To exacerbate the challenges facing the contractor, the body corporate of Bencorrum Towers imposed a restricted working schedule; 09h00 to 15h00 Mondays to Fridays, with no work permitted on weekends and public holidays.
Every window in the block will be sealed with Sikaflex-11 FC, a one-part, moisture-curing elastic joint sealant and multi-purpose adhesive based on polyurethane. Its non-sag consistency greatly facilitates sealing of overhead and vertical joints. Solvent-free and odourless, Sikaflex-11 FC provides high quality adhesion, bubble-free curing, good mechanical resistance and importantly, high quality weathering and ageing resistance.
While before-and-after photographs of completed sections at Bencorrum Towers bear testimony to the quality and ease of application of these outstanding Sika products, the ensuing years will prove their durability and efficacy. When the project is completed, long suffering residents, who have endured years of maladministration and are now personally managing their building, will once again feel proud to reside at Bencorrum Towers.