Inside Sydney’s Opal Tower
It was an unhappy Christmas for the residents of Sydney’s Opal Tower when cracks appeared in the building’s concrete structure. Now, an investigation into the cause of the defects is shaking up NSW’s high-rise building laws. By Shane Conroy
Brilliant from every aspect. That was the sales pitch for the new 36-storey Opal Tower development in Sydney’s Olympic Park. Now, just months since construction was completed, residents could be excused for scoffing at that claim after the building was evacuated on Christmas Eve 2018 when many heard cracking in the tower’s concrete structure. According to an interim investigation report by professors Mark Hoffman, John Carter and Stephen Foster, “residents of the Opal Tower reported loud noises, including a loud ‘bang’, reportedly of internal origin and presumably associated with the structure of the building”. The report goes on to state that “early investigations of the source of these loud noises identified cracks in a load-bearing panel on level 10 of the building… and further cracking of the hob beam supporting the cracked loadbearing panel”. Subsequent investigations also revealed additional “cracked concrete structural members” on level four of the building.
Digging for answers
Investigators determined that environmental factors such as major storms, heavy rainfall, high winds and extreme changes in temperatures are “highly unlikely” to have caused the cracking, and that “there is no evidence in the documentation we have reviewed to date to indicate that the materials used in the construction were inferior in quality or did not meet the specifications required”. They also concluded that: “differential settlement of the building’s column footings is unlikely to be a contributing factor to the structural damage observed on levels four and 10.” So with environmental factors, the quality of the construction materials, and the settlement of the building’s footings all cleared as potential causes of the cracking, investigators are pointing to possible design and construction flaws as contributing factors to the cracking. While the interim report stresses that further investigations are required, investigators believe that the bearing capacities of the hob beams on levels four and 10 may be below required safety standards, and that there are a number of points on level 10 “where construction differed from design and/ or standards”. These differences include the location of reinforcing steel, inadequate cover concrete, an incomplete dowel bar, and a 20mm overhang in precast concrete panels. While investigators concede that “at this stage it is not possible to state a definitive cause for the failure of the hob beam on level 10,” the report states that it is “likely that a combination of some of the above design and construction issues led to the observed structural damage on level 10”.
Cracks in the system
Fortunately for the residents of Opal Tower, these are problems that can be fixed. Investigators have agreed in principle that the developer’s proposed three-stage rectification process is sound, pending the approval of an independent qualified structural engineering organisation. But it seems this is not an isolated problem in the construction industry. According to a 2012 survey by the City Futures Research Centre (CFRC), 72 per cent of apartment owners in New South Wales knew of defects in their strata-title complex, and 85 per cent of those buildings had been constructed since 2000. The CFRC believes that many apartment buildings across Australia are suffering “significant leaks, cracks and fire safety failings” and is calling for a rethink of current high-density urban planning regulations—and the NSW Government is listening. A new NSW strata building bond and inspections scheme came into effect in January 2018 that requires developers to put aside two per cent of the building cost in a fund that apartment owners can access to repair faults or defects in the building. The scheme also includes mandatory defect inspections and reports that should shift more responsibility for preventing and rectifying building defects on to developers. The NSW Government has also committed to a further shake-up of the state’s construction laws with the proposed introduction of a new highrise tower watchdog and registration scheme for engineers and builders that will shine a spotlight on every party involved in the construction process. “It’s all about making sure building practitioners do the right thing,” NSW Better Regulation Minister Matt Kean told reporters. “I don’t want to see another mum or dad be affected by dodgy property defects.” While that’s certainly a step in the right direction to safeguard new high-rise developments, it’s probably of little comfort to traumatised Opal Tower residents. “People are buying into the Australian dream and unfortunately this has become an Australian nightmare for us,” Opal Tower resident and Chairman of the Opal Tower Body Corporate, Shady Eskander, told a press conference. “The tree is not going to fall, but the branches are cracking.