Construction waste – a building concern
Photo Caren Davis, The Treehouse Creative
As the hillsides of Mangawhai are gradually transformed into bustling urban landscapes, with new builds popping up on every other corner, the issue of construction waste has become an ever-present topic in conversation amongst the team at Sustainable Kaipara.
Recognising that construction and demolition waste make up roughly 50 percent of waste to landfill in NZ, and the fact Mangawhai is
one of NZ’s fastest growing towns, the Sustainable Kaipara team knew action was needed in this space. The Building Out Waste in Mangawhai is a feasibility study and construction waste diversion project. With Phase One just completed, the team is now eyeing up the implementation phase – how to effect change on the ground.
Mangawhai has historically consisted of a small township, plus holiday homes. However, the area now has a rapidly expanding residential population – with Mangawhai projected to more than double by 2051, and anticipated to account for 86 percent of Kaipara's population growth over the next 30 years.
Industry engagement highlighted that builders in Mangawhai currently use an average of five skip bins (mostly nine-metre-cube bins) per new build, but some use more than 20. The feasibility study identified that with a status quo approach, there would be almost 16,000 tonnes of waste produced by new home builds and an estimated value of lost materials of $108 million by 2051.
The feasibility study identifies 13 key actions to better manage construction waste in Mangawhai. A Construction Waste Guide has been developed, which identifies the options currently available to construction companies in Mangawhai to keep valuable materials in use rather than being disposed of at the end of the line. The action plan in the study also looks at the systemic issues, including the need for a construction material sorting facility at Hakaru Re:Sort to allow for reuse of a variety of materials, and the need for targeted advocacy and education campaigns that look at specific issues or materials.
Mangawhai construction waste could be reduced by 40-45 percent, simply by diverting timber, plasterboard and metal from landfill. Diversion of a range of other materials is also very achievable. Project lead, Sarah Bray, says, “Circularity is key, we need to design out the waste from the beginning as well as focus on what needs
to be done to keep valuable resources in the loop. There’s good options available right now to move timber and metal up the waste hierarchy; plasterboard recovery will be available soon. So we’re focused on supporting the local builders to tackle these materials as a starting point.”
The project has been funded by the Ministry for the Environment and Vermont Street Partners. Project supporters include ITM Mangawhai, Smith Construction and Finess Group.
To view the feasibility study or download the construction waste guide, please visit the website. For further details email Sarah Bray.