Construction and demolition waste accounts for 40 to 50 percent of all material going to New Zealand’s landfills. The volume is staggering — and much of it doesn’t need to be there. Research indicates that at least half of construction waste could be diverted from landfill if it were properly sorted at source.
The Climate Action Campus Ōtautahi in Christchurch is demonstrating what that diversion can look like in practice, through a programme called Trash 2 Treasure.
How the Scheme Works
Trash 2 Treasure connects construction sites that have leftover or surplus building materials with community groups, schools, arts organisations, and other end users who can put those materials to work. The Campus acts as a coordination point — managing the logistics of pickup or delivery, assessing the condition and suitability of materials, and matching supply with demand.
Materials that have found second lives through the scheme include timber off-cuts, tiles, bricks, insulation batts, hardware, fixtures, and fittings. Items that would have cost money to dispose of at a tip — and that often still have real functional value — instead go directly into community projects, repair operations, or maker spaces.
Why Construction Firms Are Getting Involved
Participation in Trash 2 Treasure offers construction companies a genuine win: disposal costs are reduced, the firm can demonstrate environmental responsibility to clients and the public, and the scheme’s social impact is a positive story for companies that want to be seen as good community citizens.
For project managers, it requires a modest change in site waste management habits — separating reusable materials from general waste rather than mixing everything in the skip. This takes a small amount of additional time and planning, but the material that is diverted doesn’t need to be paid for as landfill. At current tip fees, that saving can be meaningful on a larger project.
The Broader Opportunity
Trash 2 Treasure is a Christchurch initiative, but the model is replicable. The conditions that make it work — a coordination hub, participating construction firms, and a community of end users — exist in every major NZ city. Auckland, Wellington, and Dunedin all have the density of construction activity and community organisations needed to support similar programmes.
As waste minimisation regulations tighten and construction firms face increasing pressure to reduce their environmental footprint, schemes like this will become more relevant, not less.