Blog

Allco is proud to have contributed to the success of the Auckland Central Library’s living roof—an ambitious project now delivering tangible environmental benefits after 18 months of in-depth monitoring by Auckland Council and Living Roofs Aotearoa. 

Originally completed in 2022, the 500m² green roof was designed not only to enhance the city’s sustainability goals but also to function as a research platform for understanding the performance of living roofs in New Zealand’s urban context. Allco supplied the critical waterproofing system that supports the integrity of the structure beneath the vegetation layer, ensuring long-term performance under demanding environmental conditions. 

Performance Findings that Matter to Specifiers 

Monitoring has shown that the living roof: 

• Delays and reduces peak stormwater runoff, providing a natural buffer for Auckland’s stormwater infrastructure—delaying peak flows by up to 30 minutes. 

• Significantly reduces rooftop temperatures—recording summer highs of just 26°C compared to 47°C on conventional roofs, supporting passive thermal regulation. 

• Improves urban biodiversity, attracting native bird species and invertebrates, and even hosting a naturally regenerating kōwhai tree. 

• Enhances roof membrane protection, extending its service life through insulation from UV and thermal cycling. 

These findings demonstrate that green roofs aren’t just a design trend—they are a technically proven, high-performance solution for urban resilience, stormwater management, and building efficiency. 

Allco’s Role: Waterproofing for Longevity and Confidence 

Choosing the right waterproofing system was without a doubt one of the most important steps toward the goals of preserving the iconic building, its heritage, and its contents for many years to come.  

The library’s zero fall roof set up and green roof requirement meant Allco’s Hydrotech membrane was the ideal solution for the ambitious project with the installation carried out by our experienced installers Sansom. 

A large portion of the roof area is covered by garden systems and the remaining areas are covered by gravel ballast providing both aesthetic appeal and protection for the waterproof membrane against foot traffic. 

Allco worked closely with the Babbage Consultants and our applicators Sansom on the roof design requirements, providing the necessary support and technical expertise throughout the project. 

Build Greener from the Roof Down 

Whether you’re designing for stormwater compliance, urban cooling, or enhanced building performance, green roofs can help meet multiple objectives at once—with systems backed by data and real-world performance. 

Talk to Allco’s team today about green roof solutions that work—designed to support your specs, your project, and the environment. 

Recent findings, published by Auckland Council here.