Engineers Australia has backed proposed changes to the National Construction Code that it says could prevent water leaks – the leading cause of defects in apartments and commercial buildings.

Leaks account for up to 90% of defects and cost building owners and insurance companies up to $3 billion a year, it says.

Proposed waterproofing and water shedding standard changes in the National Construction Code aim to minimise the risk of water leaking into or accumulating in a building, and to prevent redirected water from damaging nearby properties. Feedback is open until July 1 here.

“Improving standards is a responsibility that spans the entire industry, including builders, architects, developers and designers,” Engineers Australia CEO Romilly Madew said.  

“We cannot meet Australia’s unprecedented housing demand without addressing the challenges facing the industry. We fully support the government’s efforts to implement comprehensive building reforms.”

The Australian Building Codes Board has identified code changes to resolve issues around lack of subsurface water management.

The reforms are expected to reduce defects, extend building lifespans, maintain structural integrity and improve flexibility in design.

They include using gravity to naturally collect, redirect and drain water, and the removal of flat surfaces from balconies, roofs and basement floors – all common trouble spots.

New guidelines for outdoor concrete slabs are also proposed, and structural engineers must consider how slabs will sag over 10 years so the structure will continue to drain.  

Engineers Australia member Michael van Koeverden says urgent change is required because while slab membranes typically last 10-15 years, structural designs are intended to last 40-60 years.  

“When membranes fail, the structure must continue to drain water. The proposed changes to the [code] aim to address these issues by improving design and construction processes and enhancing collaboration among all parties involved in building projects,” he said.