In 2014, Victorian builder Burbank teamed up with the centre for design and society at RMIT to build Australia’s first 99 per cent waste free home in the Melbourne north-western suburb of Melton.
Constructed using a combination of design strategies such as altering the type of brick and roofing materials used and waste management strategies such as non-acceptance of over deliveries, return of packaging to suppliers and delivery of sand in bulk bags which were later used to separate recyclables, the project demonstrated what can be achieved through careful planning.
That project underscored the need for builders to think about how they can minimise or eliminate waste materials in their projects.
All up, construction and demolition activities generated 20 megatons (MT) of waste throughout Australia in calendar 2016, according to the Australian National Waste Report of that year. Of this, 12.2MT or 64 per cent was recovered through recycling and energy recovery. However, 7.1 tonnes was sent to landfill. This means construction and demolition accounted for almost one third of the 64 MT of waste generated and more than a quarter of the 27 MT sent to landfill during that year.
This raises questions about strategies builders can adopt to reduce waste in their projects. Several organisations, including governments agencies and departments as well as industry bodies such as the Master Builders Association, issue guidance on this.
First, waste should be avoided where possible. This can be achieved through careful planning during design and construction.
In design, materials which involve low volumes of waste should be chosen. In particular, consideration should be afforded to systems and/or materials which can be fabricated off site. Where possible, dimensions specified should be consistent with standard material sizes. Material use should be planned to minimise waste generation. This is especially the case with off-cuts. Assets should be designed for flexibility over their intended lifespan.
During construction, methods which are chosen should minimise cut and fill on site. It is also helpful to plan and seek recycled materials. Potentially, waste generated during demolition or on works at nearby locations could be reused.
Second, waste should be reduced through purchasing.
To minimise over-ordering and encourage recycled material use, purchasing activities should be tightly controlled. Whilst taking care to avoid damaging materials during delivery, goods should be purchased with the minimum required level of packaging. The need to over-order can also be lessened through effective site security and reduced opportunities for theft.
Finally, materials should be reused and recycled where possible. This is achieved through waste management plans which are supported by the site management plan.
First, it is important to separate as much waste is feasible. Where space allows, this should be made be done on site. Exactly where materials will be deposited and stacked should be determined before goods arrive. Separate bins (colour coded) should be provided for recycling and for waste.
Regular waste bins for food scraps and other household waste generated during construction are also needed. Where possible, trucks from suppliers should be back-loaded with waste products. Waste service providers should be consulted about options for disposal.
When thinking about this, it is useful to see how strategies could be applied to different materials. In their Smart Waste Guide 2014, the Master Builders Association of Western Australia (MBA WA) describes several examples.
Take bricks. These, Master Builders says, could be dropped around the perimeter to prevent damage during transportation to their place of use. Since softer mortar saves cement and helps in recycling, an appropriate mortar strength should be used. Brick straps should be set aside for recycling. Brick suppliers who maintain active recycling programs should be used. Areas should be designated for mixing and washdown.
For electrical services, meanwhile, Master Builders recommends using sub-boards and planning wiring to reduce wiring distance, quantity, waste and cost. By stripping insulation from copper in respect of off-cuts, the copper can be sold. Using PVC-free insulating cable will lower leach toxicity. Pulse switching and intelligent controls should also be considered to reduce cabling and energy use.
For all this to happen, you should think about who will be responsible for waste management on site and how waste management considerations might be embedded into contracts.
On the first point, responsibilities should be clearly assigned and relevant personnel informed about what they need to do. Those in charge of overseeing the plan need to be aware of their responsiblities. Likewise, workers should be clear about the plan and what they need to do.
On the second, reuse and recycling plans need to be embedded into subcontracts. To ensure subcontractors are able to factor in relevant costs when tendering, a waste management plan should be prepared and communicated prior to the tender. Subcontracts should include performance clauses in respect of waste minimisation.
Australia must reduce waste on building sites.
With a little thought, significant gains can be made.