To appreciate the importance of appropriate practices regarding waterproofing in Australia, one only need look to New Zealand.

Figures from that country’s Ministry of Business, Innovation and Employment show that no fewer than 7,018 claims have been made for more than 10,000 properties under a financial assistance package which resulted from literally thousands of homes being built during the 1990s which did not meet weathertightness standards.

That raises questions as to whether something similar could happen in Australia.

The short answer is yes, and furthermore, we are seeing an increasing number of claims and a rising volume of litigation in this area across a number of jurisdictions throughout the country.

Indeed, it is worth bearing in mind that the Building Code of Australia 1996 was largely modelled on the New Zealand Building Code. Moreover, there are a number of problems in this area with regard to both the Building Code itself and some of the practices which are occurring on the ground.

The first of these revolves around the water egress provisions of Code itself, which specify that a drainage system for the disposal of surface water must convey the water to an appropriate outfall, avoid water entry into the building and avoid damaging the building. The Code fails to stipulate, however, what must be done to achieve this. This is a classic performance clause, specifying a required outcome but affording too much latitude in how to deliver on that outcome – in particular with regard to the lack of mandatory requirement for a lip, step or discernible descending outflow gradient on balconies. The wording, too, is problematic.

With regard to current practices, too many cases of building damage are happening as a result of water entering apartments and homes and the objectives of the BCA in this area thus not being met.

One problem revolves around balconies being built perfectly horizontal to internal floors of apartments without any outfall. A further challenge revolves around the difficulty in certifiers making reliable assessments as to the potential for water penetration short of having each and every apartment balcony individually tested prior to the issuing of occupancy permits.

These are serious problems. Water penetration not only causes property damage such as stalactites in basements and rotting carpets, it creates significant health risks in terms of respiratory ailments: a recent study performed as part of an international research effort involving 46,000 children across 20 countries found extensive evidence of a link between living in damp or mouldy homes and conditions such as asthma, allergies, hay fever and eczema.

Leaky homes created massive problems in New Zealand. If Australia is to avoid similar problems, we must act now.