Construction and demolition waste is estimated to make up half of all New Zealand waste. With the majority of this going to landfill, there’s growing recognition that, as an industry, we need to do better.
On average, every Kiwi home constructed generates four tonnes of waste, with an Auckland study finding that construction waste, by weight, is made up of timber (20%), plasterboard (13%), packaging (5%), metal (5%) and other (45%). Realising there is work to be done, more and more Kiwi construction firms are integrating environmentally sustainable practices into their business.
A recent case study carried out by the Construction Sector Accord, in conjunction with Naylor Love and Auckland Council, found that not only did adopting waste reduction practices make sense environmentally, but financially too. Researchers and projects participants agreed it was a win-win, with Naylor Love reducing its operational costs by diverting over 90% of its construction waste away from landfill.
Naylor Love environment manager Annie Day prompted the project. With the company for over 19 years, Annie’s passion for protecting the planet sparked an interest in reducing amounts of waste being sent to landfill.
Like many other construction businesses, Naylor Love initially had no road map for how it could adopt more environmentally sustainable practices. Annie started upskilling herself, completing training courses with Otago Polytechnic Sustainable Practice Level 5, Green Star and Homestar training courses with New Zealand Green Building Council.
This training helped Naylor Love plan the steps it needed to become more sustainable. Building materials and waste management were two areas that the company decided it needed to focus on to reduce its environmental impact.
In collaboration with Auckland Council, Annie instigated a waste trial at Naylor Love’s construction site on the Auckland University of Technology (AUT) North Campus. This involved separation of resources on site and changes to how the company used and disposed of its leftover building materials.
At the end of the trial period, the company found it had diverted over 90 percent of its construction waste away from landfill. On top of this significant leap, the new approach had allowed the company to make a saving of 40 percent on their usual landfill costs.
Annie told a ‘Building out waste in the construction’ seminar this winter, that the results of the trial had exceeded expectations on several fronts. “We saw we were reducing waste but also saving money, and just how much we were saving surprised us.
“The ultimate aim is for companies to design out waste from the outset. We need to shift perspectives to get people seeing that waste is an asset.”
Current statutory requirements
The Building Act 2004 includes sustainability principles that MBIE and building consent authorities must take account of, including ‘the efficient and sustainable use of materials and the reduction of waste during the construction process’.
In July 2021, the Government began to expand the cover of the waste disposal levy. Construction and demolition fill (class 2) now attracts a levy of $20 per tonne, which will rise to $30 per tonne by July 2024. The levy will be increased in stages until it reaches $60 per tonne at municipal landfills by then.
In December 2022, the Government proposed amendments to the Building Act that will include making it mandatory to create a waste minimisation plan for certain building or demolition work. A bill will go before Parliament this year and the changes will be phased in over time. The Homestar rating tool for residential buildings currently awards points for diverting waste from landfill and the Green Star rating scheme for commercial buildings also rewards waste diversion.
What can company leaders do to make a change?
Do a sustainability course to upskill key people in your business. Naylor Love picked one of their environment managers to do several training courses with the Sustainable Business Network and the New Zealand Green Building Council. Their environmental manager also gained a Certificate in Sustainable Practice (Level 5) from Otago Polytechnic.
Educate others in your company about sustainable business practices. Not everybody may be onboard at the beginning of a company's sustainability journey, so it's good to use tools, research, and data to showcase the environmental and commercial benefits of going green.
Consider developing a company sustainability strategy. This does not have to be a complicated or prolonged exercise. For example, Naylor Love's sustainability strategy fits on one short webpage.
Changes to handling material waste
During the project, Naylor Love made the following changes to the way they handled material waste:
Cable ties
Cable ties - a ubiquitous presence on most worksites. Traditional cable ties are made from nylon and are non-recyclable. Naylor Love estimated they would need approximately 8000 cable ties on two of the buildings on the AUT North Campus. After searching online, Annie found and imported a cable tie that was able to be unclipped and reused.
The reusable cable ties have been working well on the AUT North Campus worksite and Naylor Love is now using them on another worksite for attaching temporary scrim to fencing and the climbing formwork. Naylor Love is currently working with engineers at Beca and others in the industry to explore how to integrate reusable cable ties into specifications and make them available for retail purchase in New Zealand.
Soft plastics and cardboard
Soft plastics and cardboard were the bulk of the materials that were diverted from the general bin by volume. Naylor Love got in touch with Saveboard, a supplier utilising circular economy principles to upcycle packaging (soft plastics and tetra packs) to manufacture low carbon building materials. Naylor Love sends its leftover soft plastics too, and purchases hoardings from them. Once they are no longer needed, hoardings will be returned and remade into new building materials, helping to create a fully circular economy product.
PVC
Naylor Love's PVC supplier agreed to take back off-cuts so they could be remade into new pipes. The supplier, Marley, has partnered with Waste Management and Unitec on a project to minimise construction waste by breaking down PVC pipe off cuts made of PVC and HDPE and using the material to make new pipes. Waste Management arranged the logistics to pick up the leftover PVC from the AUT North Campus worksite.
Buckets
Naylor Love worked with a plastering manufacturer to take back their clean buckets and make them available for customers to reuse when mixing its dry plastering mixture. The company, STO, is now setting up a nationwide takeback scheme to ensure its buckets can be reused multiple times.
Hi-vis vests and branded clothing
Used and damaged branded work clothing was turned into a repurposed resource that had a new use on site. An innovative new product called ReTex was created. ReTex is a thick rigid sheet that is used as temporary protection for finished products (for example, for protecting timber balustrades while construction work is still ongoing).
Once ReTex reaches the end of its useful life, it will be sent back to Textile Products to be remanufactured and used again.
Plastic drink bottles
The number of plastic drink bottles thrown away on site surprised those involved in the trial. Auckland Council agreed to pick up used drink bottles from the AUT campus worksite as part of their municipal kerbside collection. As part of its induction training, Naylor Love now encourages its staff to refill and reuse their plastic drink bottles.
Timber
In collaboration with its concrete sub-contractor, most of the formwork untreated timber was de-nailed, stacked and sent to the next job to be reused. The Resource Sorters stacked lengths of timber that were longer than their arm to be reused on site.
Polystyrene
The AUT North Campus site foundations were designed to include polystyrene, as a lightweight fill between ground beams. Naylor Love partnered with the University of Auckland to research polystyrene waste. It found that the polystyrene could be remanufactured, and that the manufacturer could complete shop drawings and manufacture pre-cut shapes to reduce waste on site. As a result, Naylor Love has developed a new operating methodology to bag the polystyrene offcuts and transport them back to the manufacturer.
Waste sorting tips
Clear a space on the worksite to make a sorting area so resources can be separated easily. Organise different bins or skips (depending on size of the worksite) for different building products and materials.
Create clear signage that informs what building products and materials can be put in which bins/skips. Use WasteMINZ guidelines to develop signs.
Keep excess building products and materials as clean as possible because dirty, dusty, or contaminated goods can be rejected by recyclers and upcyclers.
Train people to sort waste, whether it’s existing staff and contractors or new labourers hired specifically for the task. It helps to find people who will take ownership of the work. Naylor Love has now developed a NZQA micro-credential for Resource Sorting, delivered nationwide by an independent facilitator.
Observe how resource sorting is being implemented on site. Annie and Auckland Council monitored what their resource sorters were doing and suggested changes along the way to ensure that building products and materials were being separated and distributed correctly.
Listen to feedback from trainees - they may find opportunities to improve resource sorting processes. If you are not able to sort waste on site, use a skip provider that offers waste sorting offsite.
Diverting resources from landfill
Conduct an inventory of the building products and materials you are using, including any packaging. Identify opportunities to reduce, reuse, recycle or upcycle the building materials in your inventory.
Here are some questions you can ask to get started:
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Will our clients/contractors work with us to reduce construction waste from this project?
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Are there reusable alternatives for building products or materials that we usually throw away?
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Can our engineers/architects change the design to create a more sustainable outcome?
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Can we change our building consent to accept an alternative product?
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Do the products we're using have a product stewardship scheme in place?
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If there's no existing product stewardship scheme, can we talk with the product manufacturer and/or supplier to consider developing a product stewardship scheme?
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Can we change to building products and materials that are more environmentally sustainable?
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Can we get creative and find a second life for products that we were going to throw away?
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Which of the products we're currently throwing away could we keep for later use?
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Can we work with waste collectors, including council, to divert building materials away from landfill?
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Build relationships with clients, contractors, architects, engineers, product manufacturers, suppliers, waste collectors and local councils. Well-developed relationships with these project partners will allow your business to improve your ability to reduce, reuse, recycle and upcycle excess building products and materials.
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Have an environmental champion/s to drive this work. One way to do this is to find people within your company who are already passionate about environmental issues - people like Annie.
To check on the latest building work consent developments and updates on flood and cyclone-related repair work, visit www.building.govt.nz
