Citi-Con’s extensive skills and experience have been harnessed to successfully complete major concrete repairs at two apartment blocks in Tshwane, Gauteng.

This leading specialist contractor commenced working on the project in October 2021. The repairs have been progressing according to schedule and Citi-Con is confident that it will finalise the project by the contractual completion date.

Greene Consulting Engineers is overseeing the repairs to Northshore apartments, located in the Northshore Complex in Wilkinson Street, Kilner Park. This leading consulting engineering firm has been involved in the project since 2016 when it first inspected the condition of the structure on behalf of the Northshore body corporate. While only minor damage was identified at the time, Greene Consulting Engineers suggested that the body corporate started preparing to undertake major repairs at a later stage. The firm also determined an estimated cost of the works to help the body corporate budget for the anticipated concrete repairs.

A second condition assessment was undertaken in 2019. This was when Greene Consulting Engineers identified significant concerns at both apartment blocks. Due to extensive corrosion of the steel handrails’ cast-in-plates, spalling of the concrete balconies was now visible. Spalling of the concrete columns and beams due to the deterioration of the handrail support posts over time was also noted by the team of engineers. Moreover, the handrail cast-in plates at other fixing points on the various floors of the apartment blocks had corroded causing the tiles and floor screed to lift.

Greene Consulting Engineers, therefore, updated the initial inspection report and completed a concrete repair method statement, which included a new estimated cost of the proposed works, on behalf of the body corporate. The repairs then went out to tender and various specialist contractors were invited to bid for the work.

Citi-Con was awarded the contract based on its impressive track record providing turnkey building revamp and renovation services to the commercial, industrial and residential property sectors. Moreover, Greene Consulting Engineers had worked with Citi-Con on a previous project and could, therefore, attest to the high quality of the specialist contractor’s workmanship.

Importantly, Citi-Con was also able to provide valuable insight to help improve the repair method.

For example, Andre Vermeulen, a Director of Citi-Con, suggested a more practical means of undertaking the extensive repairs to the two six-storey apartment blocks.

 “We proposed rope access and mobile boom lifts be used to access the many work areas as an alternative to installing tons of scaffolding outside the structure. Our state-of-the-art systems have provided a significantly faster, more efficient and safer means of undertaking the concrete repairs. At the same time, they are also a less intrusive solution for working in an operational area such as this as our team does not have to gain access to the scaffolding via the various apartments,” Vermeulen says.

Mark Manthe, Director of the Structural Division of Greene Consulting Engineers, who is leading the team of engineers working on this project, explains the concrete repair process. “The contracting team first breaks out all the loose concrete to achieve a sound substrate, with saw cuts of between 10mm to 15mm in depth undertaken to prevent ‘featheredging’. Where the concrete cover is less than 30mm thick, rebar is cut back after placement. Dust is removed from the rebar using steel cup brushes. Loose concrete is broken out to at least 100mm past the corroded areas. This is to expose the rebar and ensure that it is clean. Meanwhile, severely corroded rebar is removed. It is replaced with new reinforcing steel that is grouted in with repair mortar. The rebar is then primed with Pro-Struct 688 and a Stoncor V100 concrete repair mortar that are both applied according to the manufacturers’ specifications. Where there is insufficient cover over the rebar, the beam, column or face of the balcony are evenly plastered using a V100 repair mortar from corner to corner.”

One seasoned Citi-Con site agent and 10 skilled employees have been deployed to the worksite. They are also tasked with ensuring a clean and safe environment for occupants and visitors. All materials that are not being used are stored in designated areas to avoid obstructing walkways and other heavily trafficked areas. No hazardous materials are being used for this project and all rubble is being disposed of in selected areas before being spoiled. The various working areas have also been barricaded and are constantly monitored and controlled by Citi-Con representatives.

Vermeulen says that he is proud of his team’s work on this project thus far. “To date, it has been a fairly straight forward project with very few challenges for a company that has refined and honed its concrete repair techniques over many years. Certainly, excellent team dynamics between Citi-Con and the engineering team has also played a large part in the success of the project thus far. We are looking forward to successfully completing another project with Greene Consulting Engineers,” he concludes.