Path towards cleaner, smarter building sites by tackling polystyrene construction waste
Polystyrene has long been used in New Zealand’s construction industry, valued for its insulation properties, lightweight nature, recyclability and affordability. But its widespread use, particularly of expanded polystyrene (EPS), comes with a significant environmental cost when it is not properly managed on site.
Auckland Council senior waste planning specialist Mark Roberts says the construction sector is waking up to the need for smarter polystyrene management thanks to efforts by industry leaders and waste minimisation advocates.
“From improved site practices to innovative recycling solutions, to using more sustainable alternatives, we are seeing a shift towards greater accountability and environmental stewardship across the construction sector,” says Roberts. “Builders and suppliers are recognising that managing and preventing polystyrene waste isn’t just good practice, it’s essential for protecting our ecosystems and meeting community expectations.”
Problem: lightweight, litter-prone, enduring
EPS is commonly used in concrete slabs, insulation panels, underfloor systems, and packaging for building materials. While it’s effective in its function, its physical properties can make it a persistent pollutant.
“Once littered, polystyrene is difficult to recover and can persist in the environment for decades. Its lightweight nature means it’s easily blown off-site, ending up in stormwater systems and potentially our oceans. Even though it makes up a small fraction of construction waste by weight, its visibility and environmental impact are disproportionately high – making it a priority for better management and recovery,” says Roberts.
Industry response: education, containment, collaboration
One company leading the way in product stewardship of its polystyrene products is Expol. Expol has developed a suite of resources aimed at educating builders and site managers on best practices for handling EPS.
“Expol encourage the use of best practice for handling of polystyrene on construction sites. These best practices, combined with product stewardship programmes, will reduce the potential impact of polystyrene to the environment on building sites,” says Cameron Brooks, sustainability and special projects manager.
Key recommendations include:
• Using designated containment bags for offcuts and waste.
• Securing loose materials to prevent wind dispersal.
• Training staff on the environmental risks of polystyrene litter.
• Partnering with recyclers to ensure clean EPS is diverted from landfill.
Expol also operates a nationwide take-back scheme, allowing builders to return clean polystyrene waste to Expol for recycling. This closed-loop system helps reduce landfill pressure and supports the production of new EPS products from recovered material.
Council-led success: Auckland’s waste diversion model
Auckland Council has demonstrated what’s possible when local government gets behind construction waste minimisation. In a 2022 pilot project, more than 90% of building waste from selected sites was diverted from landfill thanks to careful sorting, contractor engagement, and collaboration with recycling providers.
While the pilot focused on a broad range of materials, including timber, plasterboard, and metals, it also highlighted the importance of managing polystyrene. Clean EPS was successfully separated and sent to recyclers, showing that with the right systems in place, even problematic materials can be recovered.
Challenges and opportunities ahead
Despite these successes, barriers remain says Roberts. Contamination is a major issue: polystyrene mixed with concrete, adhesives, or other debris cannot be recycled and often ends up in landfill. There’s also a lack of awareness among smaller operators, who may not have access to recycling facilities or understand the environmental impact of EPS litter.
Roberts says there is need for a national strategy, including:
• Standardised site protocols for EPS handling.
• Incentives for recycling, such as reduced disposal fees or rebates.
• Greater manufacturer responsibility, including product stewardship schemes.
• Improved data collection to track polystyrene use and recovery rates.
Technology also presents opportunities. Innovations in EPS alternatives, such as modular systems that reduce offcuts, could help phase out problematic products over time.
Builders and site managers looking to improve their polystyrene waste practices have a growing number of resources and services available across New Zealand, including:
• Expol recycling programmes – Expol offers tailored recycling services for construction sites using their products. Builders receive collection bags with deliveries and can schedule pickups via the Expol Live App or by emailing pickup@expol.co.nz. Expol also operates drop-off points for household quantities at over 25 Mitre 10 stores nationwide.
• Plastics New Zealand EPS recycling initiative – Plastics NZ supports better handling of EPS on building sites through its ‘Polystyrene on building sites’ initiative. Member companies offer recycling services for clean offcuts and provide guidance on best practices.
• Community recycling centres and transfer stations – Builders in Auckland can access community recycling centres and transfer stations that accept clean polystyrene. A full list is available on the Auckland Council website.
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