Opal Tower: 3,000 evacuated from a 4-month-old tower

Opal Tower, a four-month-old residential tower at Sydney Olympic Park, was evacuated on Christmas Eve 2018 after residents reported cracking noises on the tenth floor. Around 3,000 people were moved out of the surrounding area overnight, and 51 units were declared unsafe and off-limits. Engineers who first assessed the site said the building appeared to have shifted by up to 2 millimetres.

The builder, Icon, denied the job had been rushed and insisted the building was structurally sound, while the developer, Ecove, and its principal Bassam Aflak denied any corners had been cut. The engineer WSP led the investigation, joined by Kajima Corporation, the Japanese construction giant that is Icon's majority owner, and New South Wales Planning Minister Anthony Roberts appointed two engineering professors to review the cause.

An independent report released in February 2019 found the tower's critical support beams had been under-designed and some were cast in lower-strength concrete, leaving them susceptible to "bursting". The building was judged structurally sound overall, but with several structural and construction issues — and residents stayed out while permanent remedial works were carried out.

Owners were left with apartments they could not occupy or rent. Icon reimbursed them for rental loss but stopped covering the cost of alternative accommodation in May 2019, and some units were still uninhabitable months after the evacuation. Six months later Mascot Towers, another Sydney apartment block, was evacuated for cracking, turning Opal Tower into the reference point for a national argument about who checks quality in a construction boom.