Posted 9 Jun
Words by Sarah Keenihan.
Trinity Church stands near the corner of North Terrace and Morphett Street in Adelaide. Built more than 165 years ago, it’s thought to be one of the oldest buildings constructed by colonial Australians in this state.
But most buildings don’t last that long – perhaps 50, maybe 100 years if you’re lucky.
PhD candidate Gabriela Dias Guimaraes is interested in the lifecycle of buildings – and in particular, calculating the environmental impact from all waste generated during a building’s existence.
“For most people, the idea of ‘sustainable construction’ makes them think of solar panels and green roofs,” Gabriela said.
“But we really need to be thinking more deeply about all stages of construction, right from where materials come from, how they’re made and what happens to them when a building is demolished.”
Gabriela has undergraduate and master’s degrees in civil engineering. Through her postgraduate research at UniSA Creative, she’s creating a framework that will help designers, architects and engineers factor in environmental considerations related to construction and demolition waste for all the phases of a building’s life.
Working in a bubble
Including environmental considerations in lifecycle planning for buildings sounds simple enough. But the problem with the construction industry is that everyone operates in their own little bubbles.
The carpenters know where to source wood and which nails are best for certain types of framing. The concreters understand how to mix the right blend of sand, cement and water to create a slurry that will harden to form a solid foundation. “Brickies” lay bricks made of fired clay or shale, secured with mortar in between.
However Gabriela says environmental concerns aren’t usually included in these individual steps, let alone as an overall calculation.
“Tracking down the impact of waste from all these different parts of a building can be really complicated, because sometimes the tradies don’t even fully know what goes on before or after they’ve finished their own bit of work,” Gabriela says.
“So most of the time there’s nobody with the information or expertise to be able to make big picture, long-term decisions with environmental considerations in mind when a building is being designed.”
As one part of her research, Gabriela aims to create a database of different building materials, and rate them on their environmental impact based on the waste that is generated from building start to building end.
Helping designers make the right decisions
Architects and designers don’t use paper and pen to plan buildings these days. Instead, they apply software packages like AutoCAD and Draftsight to digitally navigate their way through projects. As a step further, they can also apply a process called building information modelling, or BIM, where you can add and manage different information relating to the planned build.
“BIM uses 3D visualisations to pull together lots of different parts of the building process – not just design, but also cost and timeline planning,” Gabriela explained.
Gabriela hopes her research will help form an extra piece of software that can plug into these existing design programs to add another layer, one that contains all of the environmental considerations of a building’s construction and demolition waste.
“Sometimes small decisions made early in design, like choosing between two different types of material for a building’s façade (the bit on the outside), can make a huge difference in environmental impact over a building’s lifecycle,” Gabriela says.
“With a good design plug-in, we can make it easy and quick for designers to choose low environmental impact materials.”
Gabriela imagines the software could end up giving designers a red or green light on their computer screen if their chosen materials failed or met certain environmental benchmarks, for example.
The big picture is complicated
It’s not always clear-cut which materials are the best choice for our environment when you expand design thinking to include the lifetime of a building.
Here’s an example: consider the choice between wood and aluminium for frames within the walls of a building.
“In the case of timber, you have to factor in maintaining the forest it came from, chopping down the tree and processing and transporting the timber,” Gabriela explained.
“For aluminium, there’s mining, mineral processing and transport – and certainly these steps can have high environmental impact.”
But then things get more complicated when you also factor in waste management, like demolition and recycling.
“If you put wood in landfill, it breaks down slowly and is a major source of greenhouse gas emissions,” Gabriela says.
“In contrast, aluminium can be collected, melted down and used again for another project.”
Assumptions can be flipped on their head when you think about the full picture and not just individual steps in building design and construction. For Gabriela, the key to a successful lifetime impact tool will be one that allows designers to easily see which choices are the most sustainable before the foundations on a new building are even laid.