In an era increasingly defined by water scarcity and climate uncertainty, the longevity and resilience of water infrastructure becomes paramount. Emblematic of this consistently increasing focus on critical urban structures, the recent joint refurbishment of Sydney’s Prospect Reservoir highlights the significance and environmental benefits of proactive maintenance.

Owned and managed by Water NSW, this crucial asset has been supplying drinking water to Greater Sydney’s residents since 1888. Recognising the importance of proactive maintenance to secure this resource, Sydney Water and Waternish Pty Ltd, teamed up to deliver repair works to address a pivotal issue: the deterioration of joint sealants within a key weir structure.

The integrity of water infrastructure often depends on the performance of seemingly small components, and in this case, weakened joint sealants posed a significant risk to the reservoir's substructure, threatening its long-term viability. Making matters more complex were the unpredictable water flows through the weir, and the vital need for repairs to occur both above and below the waterline while the system remained operational. Consulting engineers, Arup, were tasked with devising a solution that delivered not only immediate waterproofing, but also bolstered the overall sustainability of this essential water asset.

Sika’s tailored solutions


Sika's proven track record in waterproofing and joint sealing made their expertise invaluable. Working in close collaboration with Arup, their technical team carefully assessed the unique challenges faced at each repair site. This led to a multifaceted solution, employing a range of Sika products selected for their superior performance under specific conditions.

Above the waterline, the focus was on long-term protection against the wear and tear caused by exposure to the elements. After meticulous removal of the existing sealant and thorough joint preparation, engineers applied Sikaflex® PRO-3 Purform®, a high-performance sealant that creates a robust barrier designed for longevity. To further safeguard this area, Sika's waterproofing tape was applied, and it will ultimately be reinforced with the sustainable Combiflex SG system, EPDM rubber, and a mechanically fixed steel cover plate for maximum protection.

Below the waterline, a different challenge emerged – ensuring a watertight seal even with the joints fully submerged. Sika's specialised injection systems were essential. First, Sika® Injection-111, an expanding foam, was used to skillfully displace water within the joint. Once a dry environment was achieved, an application of Sika® Injection-306, which is an acrylate resin, provided the final barrier against water ingress.

Beyond immediate repairs


While the joint refurbishment of Prospect Reservoir expertly addressed the issue at hand, this initiative exemplifies a commitment to sustainability that extends beyond solving a pressing problem.

Sika’s outstanding product range is renowned for premium durability and resilience in the most demanding conditions, and specifying their high-performing products is bound to significantly enhance the lifespan of the reservoir’s infrastructure. This timely refurbishment is going to reduce the frequency of future repairs, minimising the environmental impact and cost associated with frequent maintenance cycles, as well as decrease the potential for disruptions to the water supply caused by unexpected failures in the system. In addition, the initiative clearly demonstrates that even targeted maintenance – when executed with a focus on advanced, long-lasting materials and techniques – positively impacts the sustainability of critical water infrastructure.

This commitment to advancing sustainable outcomes – internally and across the broader industry – is one of the cornerstones of Sika’s environmental ethos. “Sustainability is an overarching principle guiding our growth strategy and innovation at every level,” explains Karen Amery, Project Manager at Sika Australia.  She explains that Sika’s strategic plan prioritises sustainable materials and solutions in all new product development, while their dedicated R&D facility focuses on evaluating sustainable materials, packaging options, and other solutions.


“We see Sika as an enabler,” Karen adds. “Helping industry professionals reduce their environmental footprint by providing innovative solutions is an essential aspect of our sustainability strategy. Our technologies position Sika strongly within the industry's journey towards climate neutrality.” Reflecting the company’s unwavering commitment to sustainable innovation, outstanding durability and exceptional performance, Sika’s offering is a reliable and environmentally forward choice for any project – especially as critical as this one.

This joint refurbishment project exemplifies the power of proactive maintenance, advanced material solutions, and a commitment to sustainability in safeguarding critical infrastructure. By specifying durable, high-performance Sika products, the project team extended the reservoir's lifespan, reducing both the environmental impact of future repairs and the risk of costly disruptions to such an essential water supply. This collaboration underscores the industry's focus on long-term sustainability and demonstrates the tangible impact Sika's materials have in ensuring the resilience of critical water systems for generations to come.