Designing out waste at the very start saves time and money, and it’s green
“Better, faster, cheaper is what clients want.” That, points out Robin Baldwin, senior engineer at Halcrow, is what drives projects. And designing out waste at the outset can actually help the industry deliver better, more sustainable projects in less time and for less money. As well, of course, as decreasing its environmental impact.
For example, ordering the correct amount and sizes of material for a building saves money and avoids waste needing to be sent to landfill.
Those advocating designing out waste – which covers activities affecting all stages of project delivery – say implementation is most effective at the beginning of a project, and has the added benefit of making buildings more sustainable, an issue high on the agenda of both the government and the public.
As Baldwin, who has compiled a report on designing out waste on behalf of WRAP, puts it: “The earlier you put waste on the agenda, the greater the impact will be. The client has to take the lead, then you have a framework for carrying out waste minimisation.”
A more flexible approach to designing out waste at the outset also helps. “Forward-thinking architects and engineers are getting involved more, and earlier, with the supply chain,” says Baldwin. Changing the mindset of those involved in a project is key, and involving engineers, sub-contractors and architects at the masterplanning stage creates a unified approach.
Research carried out by WRAP has found that off-site construction generates up to 80% less waste than site-based building methods. Off-site specialist Yorkon says it has managed to reduced the amount of waste it sends to landfill sites by 50% in three years.
One advantage of off-site manufacturing is that low-value, high-volume materials, such as adhesives and fastenings, can be delivered directly to the production line, eliminating packaging. And dust produced during manufacturing can be reused to produce warm air to heat the factory, and the wood chips generated can be sold on.
Another argument in favour of factory building is that it creates a more productive working environment, which decreases waste. For example, because materials are stored under cover and in controlled conditions, weather damage is reduced, while it can be easier to sort waste materials for recycling.
Standardising design elements
David Johnson, Yorkon director and general manager, says that the company has standardised its product offering to avoid waste. Producing standard plasterboard sheet sizes is one way in which the company does this. “It’s not about recycling it, it’s about not creating it,” says Johnson. “We have spent a lot of time and effort designing our products, minimising the materials we use.”
The earlier you put waste on the agenda, the greater the impact will be. The client has to take the lead, then you have a framework for carrying out waste minimisation
The point is to maximise the use of standard width materials, which in turn minimises the amount of cutting to fit. Johnson estimates that Yorkon produces around 5% waste at its off-site factories, of which two-thirds is recycled. For many clients, including the major retailers like Tesco and Sainsbury, standardised modular designs make sense. “These stores are like meccano sets,” says Baldwin. By optimising layouts, there is no need to cut boards, which is very wasteful – and costly.
Reusing demolition waste
The Olympic Delivery Authority, which claims that it will deliver the “greenest games” ever in 2012, is reusing waste material right from the start – before a single brick has been laid for the venues. Fertile topsoil dug up during excavations for the Olympic Park will be reused within the Olympic gardens. The less fertile bottom soil will help to raise ground levels for Zaha Hadid’s Aquatic Centre. This approach is not unique to the ODA – projects increasingly reuse soil waste before construction starts.
The construction industry cannot ignore the drive, from both the government and the public, for more sustainable building practice. This can be achieved through reducing the carbon footprint of the industry as well as lowering waste on sites. And what is more, the two are inextricably linked. A report, led by consultant Davis Langdon in conjunction with contractor Wates and WRAP, points out that large amounts of waste sent to landfill result in methane emissions which contribute to climate change.
“Sustainability has risen up the agenda,” says Johnson – and those talking about it include some of the industry's biggest clients, such Tesco, BAA, main contractors, local health and education authorities.
The business case
Over-ordering of materials, particularly on housing sites, is a common problem, points out Halcrow’s Baldwin. “It is a big issue and it is difficult to get people out of that mindset. You won’t get a pat on the back if you run out of materials before the end of a job.”
However, if quantities are reviewed through the life of a project, there is a greater likelihood that the right amounts will be requested. That way, a company can save money by not over-buying, or by transporting waste at the end of a project, either to landfill or to be recycled.
“The business case is compelling,” he says. “The issue is changing people’s habits and perceptions.”