Ditching the skip

With a new project to build eight terraced townhouses in Auckland he wanted to transform the construction process to reduce waste. He set an ambitious target to divert 90% of waste by weight generated on site from landfill.

Similar developments typically produce approximately 16 tonnes of waste - that’s about the same weight as eight cars.

To ditch the skip, Nigel contacted Mark Roberts, a Senior Waste Planning Adviser at Auckland Council for advice.

They collaborated with Terri-Ann Berry and Joanne Low from Unitec’s Environmental Solutions Research Centre (ESRC) and David Knight from Junk Run to develop a Site Waste Management Plan for the build.

Designated bins and bags were introduced to the site for collecting wood, metal and soft plastics, while hazardous wastes and paint tins were kept separate.

Joanne says there is generally a lack of awareness and knowledge on construction sites when it comes to waste and recycling.

To prepare staff and subcontractors for this multi-build project, the ESRC delivered training on the “how to” of waste sorting. To make things easier bins were clearly labelled and included pictures for quick reference.

Terri-Ann notes that this sort of clear signage is essential for success, as is ongoing monitoring to ensure correct waste separation.

David adds that changing current behaviours for more sustainable onsite solutions can be a challenge for some. The sorting system meant that those not following the waste minimisation plan could be identified easily and provided with more support to get it right.

Plastic waste from the site was delivered to Unitec’s Engineering Department where it was analysed and sent out to appropriate recyclers, such as saveBOARD. Other recycling bins were collected by Junk Run which included timber, cardboard, scrap metal, fence palings and posts, paper and site sweepings.

Many of these materials were delivered to community and commercial recycling operations and projects. Overall, 91% of the waste collected by Junk Run (by volume) was diverted from landfill.

A total of 22.4 tonnes of materials were collected and audited by Junk Run and ESRC, of which 18.4 tonnes was recycled or repurposed. That included 830kg of plastic waste of which a third was soft plastic. Most of the soft plastic was recycled by Hamilton-based saveBOARD.

In collaboration with waste management company Green Gorilla and commercial construction company Naylor Love, saveBOARD has been testing the logistics of soft plastics recycling between Auckland sites and their Hamilton recycling facility.

saveBOARD uses recycled soft plastic to manufacture innovative construction board products that cost roughly the same as plywood, and can be recycled back into new saveBOARD products.

More than 150 kg of PVC pipes was recycled by Marley into new products, and about 200 kg of polystyrene was processed by an Auckland region recycling service, ultimately providing a raw material for products such as skirting board and architrave extrusions. It’s expected that about 80% of all the plastic waste from the project will be recycled.

Nigel believes there is a desire to improve waste management and increase circularity in the construction and demolition sector. He hopes the success of this project helps inspire other building companies to develop site waste management plans, educate staff on improved practices and further drive change.

Collaborators:

• Unitec
• Naylor Love
• Junk Run
• Auckland Council
• saveBOARD.

Architect: The Development Collective
Date of completion: July 2022