Study finds structural defects and overcrowding concentrated in key metropolitan areas
Pockets of Sydney and Melbourne contain some of the most undesirable housing stock in Australia, with thousands of dwellings affected by defects, overcrowding and structural problems, according to new research from comparison site iSelect.
The analysis examined SA4 regions across 21 indicators, including building condition, climate, health outcomes and access to medical services, to identify areas where residents face the highest risk from substandard homes.
The study found that while most properties remain sound, Sydney and Melbourne recorded structural issues and overcrowding at rates above the national average. High-density apartment precincts and recently built medium-density projects were prominent among the worst-performing locations.
Sophie Ryan (pictured right), spokesperson at iSelect, said some of the country’s largest housing markets were under strain. “Issues such as cracks in walls, sinking foundations and plumbing problems were common, placing additional strain on residents,” she said. “These housing problems don’t just affect comfort, they could also lead to serious health impacts.”
Parramatta reported the weakest housing conditions nationally, with 11.8% of homes affected by structural problems. Within that figure, 4.8% of properties had major cracks and 3.5% showed signs of sinking or shifting foundations. Around 10% of homes in the area were classified as overcrowded.
“Overcrowding has been linked to higher rates of stress and poorer overall physical and mental health in children and adults,” Ryan pointed out.
Inner south-west Sydney and south-west Sydney displayed similar patterns, with elevated levels of plumbing faults and other structural defects. Central Sydney districts, including the inner west, CBD and inner south, recorded some of the highest overcrowding levels, indicating that housing pressures are not confined to middle- and outer-ring suburbs.
In Melbourne, the South East, North West and West also ranked within the 10 worst regions for housing conditions, albeit with a slightly different profile. These areas reported fewer cracked walls or floors but higher incidences of other structural problems alongside persistent overcrowding.
Other Sydney regions, such as Blacktown and Ryde, completed the top 10 list of areas with the poorest housing outcomes.
“Being informed about local housing conditions is important because it helps residents understand potential risks, plan for maintenance or repairs, and make decisions that protect their homes and families,” Ryan said.
By contrast, Western Australia accounted for most of the regions with the strongest housing conditions. Mandurah led the rankings, with relatively low proportions of homes experiencing structural defects, major cracking or overcrowding.
Surrounding WA areas, including south-west Perth, Bunbury and north-west Perth, also reported low rates of foundation movement and plumbing issues. More remote WA locations such as the Wheatbelt and outback areas were found to maintain better-than-average housing standards. Inner and south-east Perth likewise featured among the 10 regions with the highest-quality housing stock.
Want to be regularly updated with mortgage news and features? Get exclusive interviews, breaking news, and industry events in your inbox – subscribe to our FREE daily newsletter. You can also follow us on Facebook, X (formerly Twitter), and LinkedIn.
