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What started as a standard refurbishment and repair, evolved into a unique opportunity to create a living green roof with over two thousand low maintenance native New Zealand plants installed so far and with a further 300 to 400 plants being planted over the coming months to improve the overall coverage.

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 and allowing the development of a roof garden aimed to extend the roof’s lifespan, improve stormwater runoff, air quality and to set the example for other business and councils going forward.

“The living roof will have a range of benefits, including reducing stormwater runoff, improving air quality, protecting the roof membrane from solar damage, and increasing biodiversity and habitat opportunities for insects and birds,” says Auckland Mayor, Phill Goff. “It will be an example to other property owners in the central city to investigate installing green infrastructure, which as well as the environmental benefits, will help make our city centre a more pleasant place to work, shop and visit.”

Auckland Council project manager Rachel Devine said the living roof “seemed like the perfect opportunity to leverage and enhance the much-needed repair works.”

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 by experienced installers Sansom Construction Systems Ltd.

The existing old membrane was removed in its entirety, the exposed concrete was cleaned and prepared for the application of Hydrotech MM6125. The roofing areas, parapets, and main plant room roofs were waterproofed with a combination of Hydrotech and Casali membranes.

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 has been able to work closely with the Babbage Consultants and applicators Sansom Construction Systems Ltd on the green roof design requirements, providing the necessary support and technical expertise throughout the project.

“Sansom is very proud to have been part of this iconic project with Allco Waterproofing. Allco’s Hydrotech was selected as the ideal membrane due to its proven track record on zero fall roofs and green roof overlay,” says Steven Van Rhoon, Director, Sansom Construction Systems. “The continued support and input from Allco’s Technical Advisors and Sansom’s experience, in combination with selecting the right waterproofing membrane, were key factors in the project’s success.”

With increased demand for high-density housing and the push for greener cities, the hundreds of unused building rooftops present a perfect opportunity to change and make improvements now. Green roofs provide the space, sunlight and fresh air plants need to thrive whilst creating community spaces and allowing the growth of native New Zealand plants.

Green roof installations like Auckland Library have a proven return on investment beyond environmental benefits. To find out more about these benefits, read Allco’s article, Green Roof Benefits Far Exceed Sustainability.

Check our latest green roof case study: Auckland Central Library 

To start the green roof journey contact Allco’s technical team on tech@allco.co.nz