Building a Sustainable Future, One Less Skip at a Time

Let’s talk trash. Specifically, construction waste. 

It might not be the most glamorous topic, but it’s a massive one when we consider the health of our planet.

As we prepare for the design charrette for New Zealand’s new sustainability innovation incubator, understanding how to manage construction waste is key to reducing our environmental footprint. This public-private project not only supports green-minded SMEs and start-ups but also aims to embody sustainable building itself, making our design choices more important than ever.

Understanding Construction Waste

Construction and demolition activities are significant contributors to the global waste stream. Globally, over two billion tonnes of construction waste are generated annually, highlighting this issue's immense scale. In the UK alone, the construction industry produces a staggering 62% of the nation’s total waste and is responsible for 32% of all waste sent to landfills. 

Here in New Zealand, the picture is similarly concerning… 

Government and council documents estimate that construction and demolition waste makes up 40-50% of New Zealand’s total waste going to landfill. To put this into perspective, each new home constructed in Aotearoa generates an average of four tonnes of waste. That’s a significant environmental footprint, and it’s one that’s hard to ignore. 

So what exactly is construction waste? 

It’s not just about the leftover bricks or timber from building a house. Construction waste includes a wide range of materials, from scrap and damaged goods to packaging and short-term building materials. It also includes the waste produced by workers during the construction process. But the problem doesn’t stop there. Demolition waste is the debris left over from tearing down buildings, which adds another layer of complexity to the issue. This often contains hazardous substances that pose additional risks. 

The consequences of this massive waste generation are far-reaching. Environmentally, the limited reuse of landfill sites due to potential health hazards, the energy required for waste transportation, pollution to land, air, and water from heavy metals and toxic chemicals, and significant greenhouse gas emissions (which are estimated to make up 4% of New Zealand’s total emissions) are all major concerns.

Economically, the costs associated with construction waste are substantial. These include the cost of operating and maintaining landfill sites, the cost of transporting waste, and the loss of financial benefit from using recycled or salvaged materials. Socially, communities can be impacted by noise, dust, and traffic pollution from construction and waste transportation, as well as the potential effects of hazardous or nuisance waste on workers and the wider community. 

Effectively managing construction waste isn’t just good for the environment; it’s also a smart move economically and socially. In today’s world, where sustainability is becoming a top priority, the construction industry has a huge opportunity to lead the way. Embracing a circular economy approach where materials are reused, recovered, and given a new life rather than sent to landfill can make a meaningful impact. It’s all about getting the most out of resources and building a more responsible future. 

What is Construction Waste Management?

Construction waste management encompasses a range of practices aimed at minimising the amount of waste generated during construction and demolition activities and diverting the remaining waste away from landfills. This involves implementing strategies throughout the entire project lifecycle, from design and material selection to on-site practices and waste disposal methods. 

Key principles of effective construction waste management include:

 

·      Waste Prevention: This is the most crucial step, focusing on reducing the amount of waste generated in the first place. This can be achieved through careful planning, accurate material quantification, efficient design that minimizes offcuts, and the use of durable, long-lasting materials.

·      Waste Reduction: Implementing practices on-site to minimize waste, such as careful handling of materials, preventing damage, and optimizing cutting techniques.

·      Reuse: Finding new uses for materials on-site or in other projects without significant alteration. This can include reusing formwork timber, repurposing doors and windows, or salvaging fixtures. 

·      Recycling: Processing waste materials into new products or raw materials. Common recyclable construction materials include timber, metals, concrete, bricks, plasterboard, and some plastics. 

·      Waste Diversion: Implementing systems and processes to separate different waste streams on-site to maximize the potential for reuse and recycling, thus diverting waste from landfill. 

Sustainability and Waste in New Zealand Construction

The New Zealand government recognises the importance of sustainable practices in the construction sector. The Building Act 2004 includes sustainability principles that the Ministry of Business, Innovation and Enterprise (MBIE) and building consent authorities must consider, including the efficient and sustainable use of materials and the reduction of waste during the construction process. 

On top of that, the Waste Management Act 2008 brought in a levy on municipal landfill waste, a charge that’s not only increased over the years but also broadened to cover more types of waste. As of July 2024, the levy was $60 per tonne at municipal (Class 1) landfills and $30 per tonne for construction and demolition fill (Class 2). Further increases are scheduled, reaching $75 per tonne for Class 1 and $45 for Class 2, by July 2027. The increasing cost of landfill disposal provides a significant economic incentive for effective construction waste management practices. 

Rating tools like Homestar for residential buildings and Green Star for commercial buildings, administered by the New Zealand Green Building Council, also incentivise waste diversion by awarding points for projects that achieve significant reductions in landfill waste. Homestar aims for at least 50% diversion, with many projects achieving 60-70%, while Greenstar has seen commercial projects diverting up to 90% of site waste.

International Case Study: Austral Bricks and Veolia

An inspiring example of innovative resource recovery in the construction sector comes from Tasman, Australia. Austral Bricks, a major construction materials company, partnered with Veolia, a leading environmental services provider, in an exciting project at Horsley Park, New South Wales.

At this location, Veolia operates a landfill adjacent to an Austral Bricks production facility. Recognising the potential of the methane gas produced by decomposing waste in the landfill, the two companies collaborated to capture and utilise this gas as an alternative energy source for the brick manufacturing process. 

Previously, Veolia had used captured methane for energy generation at other facilities, but this partnership marked a deeper involvement in the end product. The captured methane is combusted and then transferred via specially designed pipes directly to the Austral Bricks facility next door. Here, the gas is used to fire up the kiln to make bricks, replacing a portion of the traditional fuel sources. 

This innovative approach offers several key environmental benefits:

 

·      Reduced reliance on fossil fuels: By utilizing landfill gas, a renewable energy source derived from waste, Austral Bricks decreases its dependence on finite fossil fuels for its manufacturing processes. 

·      Greenhouse gas emission reduction: Methane is a potent greenhouse gas. Capturing and combusting it not only provides energy but also prevents its direct release into the atmosphere, contributing to climate change mitigation.

·      Waste-to-energy solution: This projects demonstrates a practical and commercially viable way to transform a waste product into a valuable energy resource, aligning with circular economy principles. 

This partnership even received the Australian Business Award for Innovation, highlighting its significance and impact. It showcases how collaboration and a creative approach to resource recovery can lead to significant environmental and potentially economic benefits for the construction industry. 

New Zealand's Case Study: Naylor's Love

Back here in Aotearoa, construction companies are also making significant strides in reducing their waste footprint. Naylor Love, a leading construction firm, undertook a successful waste diversion trial at their construction site on Auckland University of Technology’s (AUT) North Campus. 

Recognising that construction and demolition waste constitutes a large portion of New Zealand’s landfill burden, Annie Day, one of Naylor Love’s environment managers, led the change to drastically reduce the amount of waste the company was sending to landfill. In collaboration with Auckland Council (through their Waste Minimisation and Innovation Fund and others), Naylor Love implemented a trial focused on on-site separation of resources and changes to how leftover building products and materials were used and disposed of. 

As seen in the video above, the initial steps were relatively simple but highly effective. Naylor Love created an accessible sorting area on the worksite with different bins for various materials and clear signage consistent with WasteMINZ guidelines. Recognising the importance of education, they trained their own labourers and subcontractors to become skilled “Resource Sorters” through a NZQA micro-credential that Naylor Love even made available to the wider industry.

The focus on training and on-site sorting enabled Naylor Love to significantly divert a wide range of materials including soft plastics and cardboard (sent to Saveboard for upcycling into building materials), PVC off-cuts (taken back by Marley for remanufacturing), clean STO buckets (returned for reuse), and even used hi-vis vests (remanufactured into a protective material called ReTex). Untreated timber was de-nailed and reused, and efforts were made to minimise polystyrene waste through better planning and collaboration with suppliers. 

The results of the trial were remarkable. Naylor Love successfully diverted over 90% of its construction waste by weight away from landfill, exceeding their contract obligations with AUT. Not only does this have significant environmental benefits, but it also saves an estimated 71 tonnes of waste, worth of landfill costs. This equated to over $13,000 in savings on that specific project. 

Furthermore, Naylor Love experienced indirect commercial benefits, with clients increasingly choosing them due to their strong waste management practices. The trial also fostered improved relationships with suppliers and upskilled their workforce, leading to increased environmental awareness and positive behavioural changes. Naylor Love’s success story clearly demonstrates that on-site waste sorting and a commitment to engaging the entire supply chain can lead to substantial waste diversion, cost savings, and positive environmental outcomes. 

Construction Waste Management as a Green Element

Is construction waste management a suitable showcase green element for the New Zealand government-backed sustainability innovation incubator? 

I believe it is, and here’s why:

·      Visibility and Educational Value: Though not as eye-catching as solar panels, construction waste management can be highly visible and educational. Imagine on-site sorting stations with transparent panels, allowing visitors to see the different waste streams being separated for recycling and reuse. With informative signage and interactive displays, the incubator could educate visitors on the waste generated during construction, and the associated environmental and economic benefits. This directly addresses the pressing issue of construction and demolition waste, which makes up 40-50% of New Zealand’s landfill waste.

·      Environmental Footprint: Effective waste management can significantly reduce a building’s environmental impact. By employing strategies like waste prevention, reuse, and recycling, the incubator can minimize the amount of waste sent to landfills. As mentioned above, the Naylor Love case study shows that over 90% waste diversion was achievable through on-site sorting and material handling changes. This not only reduces landfill burden but also conserves resources, cuts transportation emissions, and saves on disposal costs. 

·      Inspiration for Innovation: By showcasing these practices, the incubator can inspire tenants to adopt circular economy principles. Like the Naylor Love’s collaboration with Saveboard for upcycling soft plastics, which demonstrates the potential for industry partnerships that could spark innovative ideas for waste reduction and sustainable material development. 

·      Cost-Effectiveness and Feasibility: While initial investment in infrastructure and training is required, the long-term cost savings from reduced landfill fees make it a cost-effective choice. With rising landfill levies in New Zealand, the economic benefits of waste reduction will continue to grow, making this an increasingly viable solution. 

 

By making construction waste management a central feature of the incubator’s design and operation, we can powerfully reinforce the importance of reducing buildings’ impacts on the natural environment. This commitment will not only create a more sustainable building but also foster a culture of resourcefulness and inspire the next generation of green innovators to build a truly sustainable future, one less skip at a time.