A huge storm on Christmas Day in 2011 marked the start of six-year saga that would, in Martin Kilbane’s words, completely change his life.

The roof of the Taylors Lakes house he shared with his wife, Lorraine, and two children was damaged, and inundated with water.

Six months after the storm, Mr Kilbane noticed a patch of mould on an inside wall but didn’t think much of it. But by the following Christmas, he discovered the entire home was contaminated.

A microbiologist found that mould spurs were deep inside the wall cavities and had spread throughout the ceiling.

“The mould made the house uninhabitable,” Mr Kilbane said. “That’s when everything went pear-shaped with the insurer.”

It is a real shame that a culture of deliberate ignorance has developed.Cameron Jones, microbiologist

Mould, the dark fungus that flourishes in damp conditions, is behind many lengthy and costly disputes that are frequently ending up in court or the Victorian Civil and Administrative Tribunal.

It is a problem affecting thousands of people across the country, with fingers pointed at insurance companies, builders, plumbers, tenants, landlords and property managers.

Kim Shaw, head of insurance practice at Maurice Blackburn, said mould could have hugely damaging and expensive ramifications.

In the most extreme case she saw, an entire house needed to be demolished and rebuilt.

“It can have quite devastating consequences in those circumstances,” she said. “By then, the homeowners or the family will have to move out for two, three or four years.

“Their life is in limbo and often they have to start again from scratch.”

Coupled with the pressure of a legal battle with an insurance company, Ms Shaw said it was common for people to experience stress and anxiety. There are also serious health implications.

One family Ms Shaw represented only discovered a mould infestation in their home after they noticed their children’s asthma was worsening.

“Medical opinion was that the mould had aggravated their children’s respiratory illness,” she said.

The Kilbanes are now in the middle of a protracted legal case against their insurance company. They believe repairs organised by the insurers in the wake of the storm were poorly completed.

The majority of legal cases about mould on Ms Shaw’s desk are concerned with insurance companies, who often offer a settlement that, in some cases, will leave homeowners out of pocket.

But disputes also centre around who is primarily at fault for the mould’s growth and who should pay for the problem to be addressed, which can be hugely expensive if the root causes are major structural flaws.

The Victorian Building Authority recently undertook an inquiry into systematic building and plumbing faults in response to a string of complaints about dodgy workmanship.

“The preliminary findings indicate that water ingress is a prominent fault and in some instances may lead to mould growth,” a spokesman said.

Mould may also be traced back to careless tradespeople not allowing wet timber framing to properly dry during construction.

Cameron Jones, a microbiologist who regularly inspects properties and provides evidence at VCAT, said mould was also a problem in the rental sector, where tenants are bringing cases against landlords and property managers, and vice versa.

He has seen firsthand how reluctant all parties are to accept the responsibility to address the underlying causes of mould.

“It is a real shame that a culture of deliberate ignorance has developed around essentially an occupational and health hazard,” Dr Jones said. “It’s a massive problem and people need to take it seriously.”

In 2015, a tenant was awarded $5400 in compensation after VCAT found the landlord had breached their duty of care by failing to properly investigate and resolve a mould issue.

The Tenants Union of Victoria has expressed concern that property managers do not always seek expert opinion.

“The default position for many property managers is it’s you, just sleep with the window open or keep the bathroom fan on,” chief executive Mark O’Brien said. “It’s simply not adequate.”

“Often people will do a lot to get it under control but it doesn’t resolve the underlying problem,” he said.

The Real Estate Institute of Victoria, the peak body representing workers in the real estate industry, said mould was frequently the result of poor living habits, and tenants who did not use exhaust fans and windows appropriately.

A spokesman also said property managers should take tenants’ concerns seriously and work to rectify mould in a timely matter if it was the result of structural problems.