Right now, it is summer in Australia, and problems associated with mould are less likely to be evident.

More than likely, however, such problems will occur during the year.

Arguably, defects leading to water leaks and thus mould build up are becoming more common in high-rise buildings. This is happening as high-rise living is becoming more common in Australia.

Moreover, there has been concern about mould build-up in modern buildings in cases where ventilation is inadequate as buildings have become more airtight and responsive to demands for greater fire resistance.

Of course, mould can grow from any moisture source, so the problem can be ubiquitous.

Where it is present at levels which are considered toxic (quite low levels), health effects from mould are serious. From a mental and psychological viewpoint, mould exposure has been linked with anxiety, depression, difficulty in maintaining focus and attention and insomnia. Common physical symptoms, meanwhile, can include runny nose, sore throat, headaches and fatigue. Those with asthma or compromised immune system are often worst affected. In some cases, death can result.

From a legal viewpoint, one matter which is beyond the scope of this article involves the rights and responsibilities regarding leakage and mould between landlords and tenants in rental premises. This may be discussed in a future article.

Here, attention focuses on issues which arise between owners and builders.

In some cases, mould can be caused by factors which do not relate to a building’s design or construction. Mould can build up, for example, where there is a temperature difference between the heated interior and cold exterior of a building in winter, which can form condensation on walls and windows. Condensation and mould can further result on bathroom walls and ceilings from hot showers on cold mornings – particularly where exhaust fans are not used. Further problems can arise from closing windows where occupants are not home during the day or from units which for various reasons may not receive much sun during the day.

Where such cases occur, problems do not relate to the building’s construction and the builder does not face any liability.

Where builders can face liability, however, is where mould occurs because of problems associated with design or construction.

Examples can include:

• Rainwater build-up at the foundation which results from the ground around the home sloping inward toward the house (this may necessitate either additional landscaping to modify the slope of the ground or installation of ditches and drains to channel water away from the home)
• Poor building work which leads to inadequate ventilation or build-up of condensation
• Exposure of the frame to weather for long periods during construction
• Water leaks caused by defective building work.

In my experience, most cases with which I have dealt involve allegations of inadequate waterproofing or defective works which caused a leak.

What does the law say?

As with other states, homeowners in Victoria enjoy some protection as a result of statutory warranties which are afforded under the Domestic Building Contracts Act. These require builders and tradespeople to deliver good workmanship, use high-quality materials which are fit for purpose, complete works within contracted timeframes, use reasonable care and skill and build according to plans and specifications.

In Victoria, these warranties apply for up to ten years from the date on which an occupancy certificate is issued. In other states, the limitation period is six years from the date of occupancy certificate issuance.

Obviously, builders face liability under this regime only for problems which are under their control. The aforementioned case of mould build-up where the frame is exposed to weather during construction is one such scenario. Where mould occurs from hot showers on cold mornings, however, builders are not accountable and are not exposed to liability.

Further, there can also be disputes about who is to blame. For cases involving inadequate roof plumbing, builders may argue that the roof plumber is wholly or partly to blame. Where homeowners fail to undertake adequate maintenance, they themselves may be argued to have contributed to the problem. In multi-residential situations, owners corporations may sometimes be argued to be wholly or partially responsible for mould build up and excess water situations which occur on common property.

Where these things happen, builders may be able to claim either contractual indemnities or contributory negligence against any other party who is wholly or partly at fault. As a result, builders face liability only to the extent to which they themselves caused the problem.

Apart from statutory warranties, homeowners in Victoria may also have claims under a ‘Water Act liability’ against anyone who causes or contributes to an excess water flow from one property to another where such flow is unreasonable (similar provisions apply in most other states). The damages can relate to financial loss and damage, property damage, or ‘injury to any other person’. The latter could potentially include health impacts of mould caused by the excess water flow.

Such claims are a specialised area and only a few barristers work in this area – often pursuing claims by or against water authorities where water resources local councils administer are subject to leaks.

Again, builders face liability only for problems within their control and may be able to claim contributory negligence against others who contribute to the problem.

As is the case with many legal matters, issues involved can be complex and multi-faceted.

Specialist advice should therefore be sought by those who are either pursuing such claims or responding to claims which are pursued against them.