Construction and Demolition Waste

Waste from construction and demolition (C&D) activities is a large source of waste in New Zealand, yet is often overlooked when people think of green buildings.

The Ministry for the Environment predicts C&D waste may represent up to: 
  • 50 per cent of all waste generated in New Zealand;
  • 20 per cent of all waste going to landfill, and;
  • 80 per cent of all waste going to clean-fill.

C&D waste is a complex waste stream, made up of a wide variety of materials including concrete, plasterboard, wood, steel, brick and glass. However, managed properly, C&D waste can be reduced, re-used and recovered, dramatically reducing the amount thrown away.

One recent project to prove this theory correct is the eco-classroom ‘The Living Room’ built at Hukanui School, with much of the credit being given to the creative thinking of the primary-aged school students.

The following case study tells the story of a student-led, environmental education initiative to plan, design and build an eco-classroom at Hukanui Primary School in Chartwell. It is the first project of its type in New Zealand, and it has an ambitious waste minimising target. 

Hukanui School's eco-classroom building site The Living Room Project

Hukanui Primary School has been an Enviroschool since 1998, so students are used to thinking about, and working on, environmental action projects. It was the environmental education electives group, led by Hukanui’s enviro teacher Michelle White, that first identified the need for a dedicated environmental education space at the school that exemplified the principles of sustainability. A working group of interested students was set up to help progress the idea, and ‘The Living Room’ project began.

The project spanned over five years, with each planning step being carefully researched and documented by the students. In this way, essential information was passed on to the next year group so they could continue with the project. Various stages of the project also had support through Hamilton City Council’s Envirofund.

In 2007 the Hukanui Primary School Board of Trustees gave permission for the project to proceed and fundraising began. Construction commenced in 2009 and the classroom was ready for use Term One 2010.

The Living Room was designed to minimise the negative impacts on the environment through the use of innovative building design, practices and materials. Students researched various means of achieving this and included the following points in their design brief: 

  • built to make the most of natural sunlight and heat
  • rainwater collection tanks
  • natural ventilation – large opening doors, louvers and skylights
  • double-glazed windows to prevent heat loss in winter and remain cool in summer
  • extra thick concrete floors to absorb energy during the day and release it at night
  • untreated timber sourced from sustainable plantations (macrocarpa, poplar)
  • environmentally friendly insulation used from wool, wine bottles and recycled plastic
  • biodiversity friendly, with plans that have minimal impact on the site and maximum care for the
  • surrounding habitats during the building process
  • a sustainable outside, including native tree planting, nursery, vegetable garden,
  • beehives, bird feeders and a new location for existing recycling systems.

The classroom has a carbon footprint half the size of a ‘typical classroom’. 

Hukanui School Eco Classroom Waste Management Plan

Hukanui School students aimed to help the environment by reducing the amount of waste going to landfill during the building process, so resources were not wasted and to reduce the carbon footprint for the building during the building process. 

The students worked with Marra Construction (2004) Limited (Marra Construction) and Jodi Earwaker from Tonkin and Taylor in developing a Waste Management Plan for all stakeholders to abide by with the belief that waste minimisation is achievable. This meant that construction related to waste at all stages was either: 

  • Eliminated
  • Minimised
  • Sorted and available for ecycling rurposes

For Marra Construction this proved a progressive exercise, and meant that they needed to focus on: 

  • Ordering the right amount of product to prevent oversupply
  • Reducing inefficient resource use
  • Identifying a second-use for materials classed as ‘waste’
  • A change of mentality from having a single skip destined for landfill 

The waste minimising target was at least 70 percent of all construction waste and waste generated by people on site.

Here are how different types of waste were dealt with: 

  • Timber: Waste was avoided by sorting and stacking timber on site. Any timber products were re-used or sorted for classroom heating. Saw dust was collected and used for composting.
  • Metals: Waste metals were collected for recycling. Examples include steel off cuts, nails, roofing, iron, screws, reinforcing steel and electrical cables.
  • Organics: Food scraps were collected for the school wormery.
  • Packaging: Cardboard and paper were stacked for recycling.
  • Polystyrene: Polystyrene products were collected and recycled by an Auckland based collector.
  • Concrete: Old dug up concrete was reused and recycled.

Marra Construction was responsible for implementing the student designed waste management plan.

Jeff Lukin from Marra Construction said that “the waste management plan was not only surprisingly easy to implement, but through the induction held with all the sub-contractors everyone working on the site had buy-in and worked towards reducing their waste.” 

“In the competitive construction environment, being able to offer a sound waste management plan to reduce C&D waste going to landfill gives contractors a competitive advantage through not only being able to market themselves as environmentally conscious, but financial savings can also be made through not having to hire as many skip bins.” 

All waste during the demolition and construction was recorded on a checklist before it was removed from the site. Progress was reported on fortnightly to the students and any issues with the waste management plan were raised at this time.

The waste streams were broken down and reported on in the following areas:
  • Material
  • Clay / Soil / Sawdust
  • Timber
  • Organic Waste
  • Landfill ‘bucket’
  • Packaging plastic
  • Concrete
  • Recyclables
  • Metal – Steel, copper and iron

Ingredients for success

The Living Room was completed in December 2009, with the waste management plan being implemented very successfully. The full results have been made available, and show just 2.4m³ going to landfill. All other waste was either recycled or re-used.

When asked what the key to success was, Marra Construction and Hukanui School provided some simple questions that any contractor could ask themselves to achieve similar results:

  1. What alternative use is there for the demolition waste? Can it be recycled/re-used?
  2. How can sub-contractors be encouraged to aspire to an environmentally conscious waste management plan?
  3. What products should we be purchasing? And what suppliers should we be supporting?
  4. Are all stakeholders on board with the waste management plan?
  5. Do we have accountable systems and documentation in place?

Marra Construction have found that implementing an environmentally conscious waste management plan is not as challenging as many people may think, and it also provides opportunities to save money – for both the contractor and the client.  

Some of the key actions to ensure the Hukanui School waste management plan was successful included: 

  • Induction of builders working on site
  • Regular monitoring and reporting systems were put in place
  • Nothing left the site unless it was documented
  • There was no landfill skip
  • Dedication and enthusiasm from students, Marra Construction and sub-contractors who believe that waste minimisation is achievable in the construction environment.  
Page reviewed: 15 Apr 2016 3:32pm