Build Homes: How do I design to prevent waste and recycle and re-use on site?

Queensland-based designer builder Brett Blacklow has told us that designing first and cutting material later is a recipe for adding all sorts of costs that aren’t immediately obvious into a building.

Blacklow – who teamed up with real estate veteran Kevin Doodney to create the Smarter Small Home in response to rising housing prices throughout Australia – says he has long thought the Australian housing industry needed to design and build around building material sizes.

His approach means that rooms and walls are designed to match the size of available building materials. Any offcuts generated are then re-used elsewhere in the design.

Listen to the interview with Brett Blacklow here

Construction savings
Designing to fit materials is just good sense, argues Blacklow. “Obviously, if you design a building around material size you are going to reduce waste, and that means you are buying less materials so you are saving some money and I think today everyone understands that saving,” he says.

However Blacklow adds there are additional construction savings by designing to building material sizes including a significant reduction of onsite waste.

He says, “There is a significant cost these days for disposing of construction waste, so if you have less waste during your construction that is the second layer of saving.”

Blacklow also explains that creating a design with a focus on material sizes reduces the amount of time workers spend onsite, which in turn cuts labour costs and a project’s overall bottom line.

“If you design your building around material sizes and your people on site understand that, then they don’t need to go to the building to measure, mark out, cut, throw something in the bin, then pick it up and install it on the building,” says Blacklow.

“All they have to do is pick the product up, install it and move on.”

The Smarter Small Home responds to the housing affordability problem in Australia, with the team successfully providing the market with a house and land package for around $300,000.

Designing the lightweight, two-storey house to fit materials coming directly from the manufacturer was a key factor in keeping the cost of the project to a minimum, according to Blacklow.

He went looking for a number of key economic building materials first, and then designed the structure of the house and floor plan around them.

“Typically no one approaches it like that,” he says. “Usually the builder or designer comes up with a floor plan and then he works out how to make it stand up.”

Easy building materials installation
Often, time is money, which means maximising the speed of construction. According to Blacklow, a key way to achieve this is to select products that can be installed and finished simply.

After researching exterior cladding materials, Backlow and his team concluded there was “nothing that can touch a few of the James Hardie® products price-wise.”

He explains, “The thing I’d say about these [James Hardie] products is that if you can give me one standard flat sheet like HardieFlex™, I can give you six different finishes through the use vertical or horizontal battens.”

The sub-floor is another area where layers were reduced. Many James Hardie products are sheeted so a carpenter can cover an area 3sqm in 10 minutes, according to Blacklow.

How do I recycle and re-use on site?

Diverting waste from landfill reduces greenhouse gases by avoiding methane emissions from the breakdown of wood and other organic waste. It also cuts the amount of liquid toxins seeping into the ground from landfill areas, and encourages the use of secondary resources as an alternative to ‘virgin’ material.

Moreover, the economic benefits to recycling include reduced material cost through the re-use of materials onsite, lower material tipping fees, the sale of recyclable material, and rebates for waste material delivered to recycling facilities.

The report – A Practical Guide to Reducing Waste on Building and Construction Sites – claims there is a growing awareness in the construction industry of the recycling movement and its positive impact on landfill.

For our building, architect and home renovation readers, we has reviewed the report and identified some of the best and most efficient approaches to minimising waste.

Recycling on site: setting targets
Before you implement a waste management plan, it’s necessary to audit the waste stream on site. Once you’re aware of what waste is being generated, it’s then a matter of setting targets. This helps to focus attention on recycling and provides a framework for developing strategies.

To succeed, a waste management plan must enlist the support of management to drive its strategy. Furthermore, it’s essential that management communicate the waste targets at the onset of the project, which helps to emphasise the importance of recycling to all stakeholders.

Waste minimisation plan: the low hanging fruit
There are a number of opportunities for minimising waste that can be implemented on almost any construction site. These include:

Minimising the amount of packaging being brought onto site through contractual requirements with sub-contractors;
Requiring material suppliers to assume responsibility for waste by requesting reduced packaging or a ‘take-back’ agreement;
Ensuring sub-contractors re-use off-cuts wherever possible, either contractually or through awareness campaigns;
Encouraging subcontractors not to over-order materials, and
Practising ‘just-in-time’ delivery of construction materials to avoid waste from damage prior to use.

Re-use and recycle: opportunities for savings
It’s possible to save big dollars by initiating engagement with the growing number of waste contractors. These contractors can provide rebates for either the transport cost or the amount of recyclable material delivered … or both!

Make a few calls to the manufacturers in close proximity to the site, who may collect specific waste streams for use in their own products, and encourage product suppliers to make the move to stackable, returnable and reusable packaging.

Demolish or deconstruct?
The Practical Guide to Reducing Waste on Building and Construction Sites report also describes that the way a building is demolished often determines how effectively an individual material can be re-used or recycled.

A deconstructive demolition provides the greatest opportunity to remove materials for re-use, however the feasibility of this approach to demolition depends on the age of the building, the type of contraction and access to the site.
Plan success: get staff onboard
A waste management plan won’t succeed without the fully-fledged support of workers on site.