Sika Australia  has supplied the green roof waterproofing membrane for Australia’s largest desalination plant being built by the Victorian Government in Wonthaggi.
The green roof covers a total area of 26,000m² and incorporates 100,000 plants, forming an important part of the project's landscape architecture. Designed to provide acoustic protection, corrosion resistance, thermal control and reduced maintenance, the green roof utilises the Sika Sarnafil membrane system to create a waterproof barrier for the lightweight, structural ply substrate.
According to Geoff Heard of Fytogreen, the green roof builder and designer, the site and scale of the roof presented a number of challenges including weather, design modifications for compliance and lack of pre-existing green roof standards for Australia. The thin profile green roof features indigenous vegetation tolerant of high heat, salt drift, drought and wind, helping to integrate the plant building into the environment.
Heard explained that the Sika Sarnafil ‘G series’ polymeric sheet was ideal for the application as the waterproofing membrane needed to allow for potential movement from kilometres of joints. Key requirements for the waterproofing membrane also included UV resistance for 25 years and compatibility with the electronic ILD (international leak detection) system.

Some waterproofing membranes use sealants, adhesives or tapes to secure faulty seams, which are a common source of leaks in green roofs. The thermoplastic Sarnafil has the seams and flashings welded together using Sika Sarnafil’s automatic hot-air welder, resulting in a single monolithic layer of material that is impervious to moisture infiltration.
Heard adds that a combination of modern leak detection techniques and high quality membranes such as the Sarnafil significantly reduces the perceived risk associated with green roofs. Fytogreen adhered to a well-honed green roof construction method and ITP check procedure during the installation of the 26,000m² green roof without causing a single breach of the membrane during the roof garden installation phase, which is attributed to the membrane quality as well as Fytogreen’s attention to detail.
The Sika Sarnafil waterproofing membrane will provide ongoing protection to the structure from the intensely damp environment, allowing for ongoing irrigation and resistance to root penetration.
As the largest green roof of its type in the southern hemisphere, the Victorian Desalination Plant green roof will be the subject of two papers presented by Fytogreen and Aspect Studios for the International Green Roof Congress in Copenhagen in September 2012.