Specifying efficient use of materials and considering their impact from manufacture to disposal.
Construction and demolition produce large amounts of waste.
On this page
- costs of construction wastes
- statutory requirements
Construction and demolition waste makes up half of New Zealand’s total waste going to landfill, according to a 2015 government document. Each home constructed generates an average of four tonnes of waste. An Auckland study found that construction waste by weight is made up of timber (20%), plasterboard (13%), packaging (5%), metal (5%) and other (45%).
Most of this dumping of construction waste is unnecessary – it has been demonstrated that simply by sorting waste, at least half of it could be diverted from landfills and cleanfills. Large volumes of waste also increase the costs of a project and its environmental impact.
Costs of construction wastes
Environmental costs from waste disposal include:
- limited reuse of landfill sites due to potential health hazards
- energy required in transportation
- pollution to land, air and water from heavy metals and toxic chemicals
- greenhouse gas emissions
- unsustainable depletion of resources.
Economic costs from waste disposal include:
- cost of operating and maintaining landfill sites
- cost of transporting waste to landfills
- loss of financial benefit from using recycled or salvaged materials.
Social costs from waste disposal include:
- noise, dust and traffic pollution to the community
- effects of hazardous or nuisance waste to workers on a building site and to the community.
The Building Act 2004 contains sustainability principles that the Ministry of Business, Innovation and Enterprise (MBIE) and building consent authorities (BCAs) must take account of under the Act. These include:
- the efficient and sustainable use of materials
- the reduction of waste during the construction process.
The Waste Management Act 2008 was introduced to encourage waste minimisation and reduce waste disposal by applying a levy of $10 per tonne (excl. GST) on all waste sent to landfills. The levy aims to encourage people to think about how they dispose of materials, and provide an incentive to avoid waste as well as provide funding to help develop waste minimisation projects. More than $70 million has been spent on over 100 projects.
Some industry observers have said that the spending has had little impact on the volume of rubbish created or sent to landfills, however.
A report by Eunomia Consulting commissioned by a mix of councils and other bodies recommended extending the levy to different types of landfill, different rates for standard and inert waste, gradually lifting the rate and applying more monitoring and enforcement. Potential benefits would include a much larger proportion of waste recovered rather than going to landfill, and economic and employment benefits have been identified. There would be costs to implement the changes, but these would be lower than the economic benefits.
Waste diversion and rating tools
The Homestar rating tool for residential buildings awards points for diverting waste from landfill. At least 50% can be diverted, and often 60–70% is achieved.
(The Green Star rating scheme for commercial buildings also rewards waste diversion. The New Zealand Green Building Council reports that some commercial projects have diverted 90% of building site waste.)
Ecolabel specification coming for construction and demolition waste management
A new specification is being developed to encourage waste minimisation and resource recovery, aiming to reduce the volume of construction and demolition waste being trucked to landfills.
The New Zealand Ecolabelling Trust (which administers the Environmental Choice New Zealand ecolabel) is behind the initiative. Existing service providers and industry groups will be consulted.
Auckland Council’s Waste Minimisation and Innovation Fund supported the work with a $35,000 grant. The project, announced in early 2019, will initially focus on the Auckland Region, but the intention is that the specification would eventually be applicable New Zealand-wide.
A draft of the specification has been released and is open for comments until 13 August. You can find more details here.
Updated: 08 July 2019