After all the drama associated with the ‘leaky homes’ debacle in New Zealand over recent decades, one would think Australia would learn the lesson and practices regarding waterproofing here would be above reproach.

Yet in the Australian Capital Territory at least, recent times have seen a proliferation of construction defects and failures in this area, with outdoor balconies in large apartment complexes being the most common area of concern.

One problem area revolves around external balconies on high-rise floors being built on the same level as internal flooring and without a gradient sloping away from the apartment to allow for runoff – a phenomenon which does not allow water to migrate to an external open space, and one I am told often results from contractors either failing to provide a runoff gradient and/or not constructing a water barrier lip. Where this happens, water accumulates and washes back into the building, ruining carpets and sometimes corrupting timber flooring.

A further concern surrounds a lack of water resistant balcony tanking. This was the case in one dispute we handled recently for a Melbourne body corporate whereby serious water penetration was emanating from leaking balconies. Whilst an initial piecemeal approach to rectification on the part of a builder involved the application of a tar membrane which didn’t work, the problem was finally resolved – albeit at considerable cost to the builder – by installing steel tanking.

These problems are serious. Not only does water corrosion corrupt timber, carpet, joinery and paint work, it has been linked with concrete cancer as well as asthma linked to mildew which generates airborne toxic spores.

All this highlights a far broader area of concern: ambiguity surrounding the role of private certifiers. Unlike their peers in Victoria, New South Wales and the NT, private certifiers in the ACT are not actually allowed to issue occupancy permits. Instead, these are issued by the Crown, albeit with a peculiar provision allowing the Crown to have regard to a certifier’s certification.

This creates an absurd situation whereby the surveyor is not ultimately held responsible for the final certification and the Crown, as the effective penultimate certifier, can wind up facing significant liabilities for which it had no fault. It also creates potential situations whereby the Crown is relying upon certification carried out by the same community it disciplines and regulates. All this is a mess.

Two things should be done. One, with key indicators pointing toward a surge in litigation, Treasury should expand the budget to allow for higher levels of contingent liabilities for defective buildings.

More important, the ‘half pregnant’ approach to certification in the current Building Act must go. Instead, certification should be fully privatised and subject to more rigorous enforcement and accountability.

New Zealand’s waterproofing debacle should never have been allowed to happen. Australia, and especially the ACT, should learn from the past and make sure the same does not happen here.