For eco-conscious projects, using recycled materials is a fundamental strategy. When the recycling process itself is a low-energy one, it results in a major win in terms of reducing the carbon footprint of a project and diverting materials that were otherwise destined for landfill.
Jobsite spoke to three award-winning innovators about how they turn waste into something extraordinary.
Twenty-five years ago, Michael Kennedy, the founder of Kennedy’s Timber, realised there was an opportunity to make use of the Australian hardwood timber from telephone poles when they are decommissioned.Bridge timbers were also an opportunity he spotted that was waiting to be explored.
The quality of the wood fibre had potential for repurposing, he thought, so he worked with energy distributor Energex and the NSW Office of Environment and Heritage to develop protocols for recycling and re-using poles or bridge timbers, including those that had been treated with toxic compounds including copper chrome arsenic and boron.
There was also a need for a standard around grading the timbers in terms of their applications, so the company worked with Forest and Wood Products Australia and the Queensland Department of Tourism, Regional Development & Infrastructure to develop one.
“It’s been an evolution,” Kennedy says.
The company has grown as demand for recycled architectural and structural timbers has boomed, expanding from its Queensland base to operations across the country.
The supply chain in terms of timbers available for recycling is a healthy one. UTS Professor of structural engineering, Keith Crews, estimated in 2014 that there were 40,000 timber bridges in Australia, many nearing the end of their functional life.
Kennedy says that while some will be repaired, others will be replaced resulting in the timber becoming available.
The power pole supply is also significant, with around six million timber power poles in use across the Australian east coast states, and 200,000 being decommissioned annually.
One thing he would like to see is a higher rate of diversion of useful timber from the landfill. The company has plans to invest in new technology next year that will enable it to create architectural products from smaller pieces of reclaimed timber.
Kennedy says one of the things that is feeding demand for the product is the education and advocacy work undertaken by organisations including Planet Ark and Wood Solutions.
Kennedy says people are now starting to understand the benefits of wood in terms of its environmental friendliness, being a store of carbon, and having benefits for human well-being when used in a building.
“When you recycle there is an extra benefit,” he says.
People are now starting to understand the benefits of wood in terms of its environmental friendliness.
He says he is seeing more general construction projects also storing and reusing timber from demolition works. Recent examples the company has worked on include the award-winning Northshore Pavilion in Brisbane, which used timber reclaimed from the demolition of a wharf and timber buildings on the site.
Kennedy’s also worked with Brookfield Multiplex of the re-use of timbers from structures demolished at the site of the $135 million Portside Wharf precinct.
Another spectacular project was the Tree of Knowledge monument at Barcaldine built in 2016, which utilised over 5,000 pieces of recycled timber hand-selected by the company’s staff.
Kennedy says it is an exciting time to be in the recycled timber business.
“We are seeing a lot of innovation in wood products with things like prefab and other products that are making it easy for the builder. I see plenty of opportunity ahead.”
Roof Tiles Turned Into Design Rock Stars
Terracotta roof tiles have been one of the iconic features of Sydney, but with so many older homes being demolished to make way for new developments, they are also appearing more often in landfill. Architects Rafaello Rosselli and Luigi Rosselli found a way to rescue and re-use hundreds of the tiles for Luigi Rosselli’s new studio, the Beehive.
The tiles were used to construct a Brise Soleil façade for the building. The façade filters harsh western sunlight and allows ventilation through into the office spaces. They were also used internally as part of the fitout, and on the accessible part of the rooftop as part of the balustrade.
The distinctive and original result has won a number of awards and commendations including a NSW Architecture Award, a Sustainable Architecture commendation and a Think Brick Award.
It was built by hand by a team of eight, led by Callum Coombe, who had been working in construction while studying architecture.
“This geometry is inherently strong as well as formally expressive.”
Coombe tells Jobsite he sees architecture and construction as the same thing, so he set out to learn about the craft of architecture through building. Since working on the Beehive, he has joined the studio’s team as an Architectural Designer.
He was engaged to work on the project by the architects due to the inherent complexity of the design and the unconventional use of the terracotta roof tiles.
His first task after assisting with the schematic design was to help prototype the idea.
“Prototyping is incredibly important for such unconventional use of materials as it is where you work out the characteristics of the building material, how it works tectonically, how you can join it, fix it, glue it, slice it, drill it etc,” Coombe explains.
The testing period also enabled them to work out how to resolve the concept structurally. The façade uses a “house of cards” stacking geometry to create triangulations which are compressed between the horizontal courses above and below.
“This geometry is inherently strong as well as formally expressive.”
For structural integrity, structural grout embedded with hot dip galvanised steel between the two top and bottom tiles that make up the horizontal courses was used, and this was then tied back to steel columns with structural brackets.
“One thing we discovered through prototyping is that while the terracotta roof tile is a common module, due to the act of pulling the wet clay from the mould, and the way it was baked, there is actually a lot of variety in dimensions and shape from tile to tile,” he says.
That meant there had to be margins of tolerance inbuilt within the construction system. Spacing modules fabricated from recycled polystyrene foam were used to help position and lay the tiles, and lasers used to keep levels with the design’s margins.
The construction crew also used hundreds of timber wedges – shims – to get each tile in the right position while the grout cured.
In terms of the cost, Coombe says half the tiles were obtained for free, and the balance cost around $1 per tile.
Since completion, there have been others wanting a similar façade. Coombe says Luigi Rosselli is using the brise soleil design for some new buildings that will be under construction in the next couple of years.
Old Bottles Find a New Life
Lismore City Council has taken an advanced approach to resource recovery and reducing waste to landfill. One of their innovations, turning glass and some ceramics into sand at the Lismore materials recovery facility, won an Earth Award from the Civil Contractors Federation.
The glass sand was initially trialled for uses such as pipe bedding and has also been piloted as a replacement for sand for concrete footpaths and for road base.
The trials were successful, for it has since been used for the Nimbin Transfer Station upgrade, in roadworks including the Lismore Rainforest Botanic Gardens visitor centre upgrade and for pipe bedding for upgrades in South Lismore.
“Council is encouraging other councils to use the glass sand locally, especially as it comes from their community’s recycling efforts,” she says.
“Council is continually working on finding markets and new uses.”
The glass sand does not create any additional WHS requirements beyond working with conventional sand and aggregate.
It also has some real positives, for one, keeping glass out of landfill saves $81 per tonne in New South Wales waste levy fees.
There’s also a clear environmental dividend.
“The biggest savings are in reducing requirements for mined virgin sand and not having to transport heavy glass elsewhere for recycling.”