The case for retrofitting existing buildings over tearing down and constructing new has long been debated.
Products that aren’t built to last have created a throw-away society that is wreaking havoc on the environment, and the building sector has not been immune.
More than 20 million tonnes (or megatonnes, MT) of waste was generated in 2017 from the construction and demolition industry – more than a third of Australia’s waste production.
And nearly all of it is sent to landfill.
Principal researcher for climate change think tank Beyond Zero Emissions, Dr Dominique Hes, says Australia currently leans towards tearing down homes and buildings and starting fresh.
She says it is cheaper and easier, and we don’t “value the full life cycle and meaning of these old buildings, or the full impact of the new materials we are using”.
”Instead, people are seeing their homes as just assets.”
Which is better?
Dr Robert Crawford, an associate professor in construction at The University of Melbourne, says while there are valid arguments for both retrofitting and building new, from an environmental perspective it is almost always better to retrofit.
“Existing buildings have a significant amount of resources embedded within them, in the form of raw materials, energy and water,” he says.
“Demolishing a building and building new means that much of these resources are wasted, with many sent to landfill.
“Additional resource demands are needed, and greenhouse gas emissions, waste and pollutants are then released into the environment from the increased demand for virgin materials.”
Retrofits to make homes more sustainable and comfortable to live in can save over 50 per cent of the embedded resource demands and construction-related environmental impacts, he said.
“This is especially critical given depleting global natural resources and increasing greenhouse gas emissions and waste production.”
While in most cases retrofits impact the environment less, save on materials, and protect character and history in our cities, Dominque Hes says there are some arguments for building new.
There is a trend to knock down homes to increase density, which can equate to shorter commutes, less driving and a cut in pollution.
But that is only with the right strategies in place to create sustainable urban density. Being connected to green space, public transport and cycling infrastructure are key factors, and the buildings need to be designed to be efficient.
“The criteria for me when weighing up the options is to consider where the building is, how long it is meant to be there, will the materials last that long and can we recycle the materials if we don’t use them,” Hes says.
“If you have a home where the materials are all timber and that timber is rotting and not salvageable then rather than retrofitting it might be a matter of recycling.”
Regardless, “it is not a straightforward answer.”
Australia needs a policy upgrade
Despite hefty levies in place for sending waste to landfill in most states, and opportunities for recycling on the increase, trends show the amount of waste directed to landfill has remained relatively steady for the past decade.
In 2018, an inquiry into waste and recycling in Australia found an industry “in crisis”.
The inquiry committee took into account the Chinese Government’s decision to restrict the import of waste, but also raised “years of failure across all levels of government to make the policy decisions required to put the industry on a solid footing”.
“Australia is lagging far behind other jurisdictions which have developed policies and made investments in infrastructure and technology to establish circular economies which ensure that materials are used, collected, recovered, and re-used within a country,” the committee reported.
They outlined a host of recommendations including the Australian Government extend producer responsibility under product stewardship schemes “to ensure better environmental and social outcomes through improved design”.
Hes says stronger policy is also needed around new-build housing to ensure higher efficiency standards. Government incentives for retrofits geared towards all home owners, not just the wealthy, are needed as well.
“If you improve the performance of the home through retrofitting you will have a smaller impact, but there are cases where it doesn’t make sense, in this case you would reuse materials, and if that isn’t possible recycle them,” she says.
“In my neighbourhood it is all tear down old house and build two or three new ones, though I have my doubts that they are better thermally.
“They are reducing garden sizes and making our streets crowded with cars. The intent is that increased density is good, people will catch public transport. The problem is the policy and delivering of the public transport often doesn’t stop every home having two cars, so when one home gets turned into three then we suddenly go from two to six cars.
“Though 6 star and Building Code Australia improvements have been great, I am not convinced they are audited enough. I have taken a thermal camera through many homes and found poorly put in insulation, doors and windows, seals, etcetera.”
Hes points to projects like Energiesprong, a whole house refurbishment and new-build standard and funding approach which originated in the Netherlands, as an example of the possibilities.
Homes are retrofitted with new technologies such as prefabricated facades, insulated rooftops with solar panels, smart heating, and ventilation and cooling installations.
And what began as a small government-funded program to improve energy efficiency standards in the Dutch market has led to over 5000 homes retrofitted to net zero energy houses at no extra cost to the residents.
“People want to live in comfortable homes that don’t cost a lot to keep comfortable,” Hes says.
“Unfortunately, we have a lot of sitting stock that is difficult to keep comfortable.
“Projects like Energiesprong show that a rolling upgrade program can mean houses are retrofitted in one week, with a 30 year energy use guarantee and at no cost to the homeowner.”
Beyond Zero Emissions’ Million Jobs Plan
In June, Beyond Zero Emissions launched The Million Jobs Plan, an economic stimulus plan designed to accelerate the transition to renewable energy, significantly reduce energy bills in homes and address Australia’s chronic shortfall of social housing by building 150,000 energy-efficient social houses.
“In the Million Jobs Plan we show how we could roll out 2.5 million retrofits over five years creating 500,000 jobs around Australia,” Hes said.
She says it’s a “win, win, win,” for the economy, for people and for the environment.
“These retrofits would result in lower energy use, more comfortable homes, and therefore less need to move out and knock down buildings and rebuild.”
With the majority of homes built before the introduction of energy performance standards, many people live in homes that are hot in summer, cold in winter and use a lot of energy – making bills higher.
The plan details the benefits of simple retrofits and the potential to eliminate energy bills, especially for people living in low-income homes.
“Done well, homes made with green building materials and sustainable urban design can make healthier neighbourhoods and negate the urban heat island effect, keeping temperatures down in our suburbs during heat waves,” the plan states.
“Broader co-benefits of the buildings sector initiatives include the upskilling of thousands of construction workers to deliver high performing housing – this will set the industry up for delivering on a rapid trajectory to zero emissions across all new buildings and retrofits.”
The challenge in building sustainably for the future
University of Melbourne’s Dr Robert Crawford says the extent of sustainability measures taken to retrofit an existing building is typically left to the developer and driven by finances.
Despite the long-term financial and environmental benefits, upfront costs can be substantial.
“It can be difficult to retrofit a building with many of the current day technological and performance requirements and ensuring future adaptability as these needs change,” he says.
“Retrofitting can add substantial costs to a project as builders will factor in increased risks for unknowns and other construction-related risks of maintaining an existing building.
“It can be especially difficult to guarantee the long-term performance of existing structures and building components, and builders don’t tend to want to take the associated risks of providing a warranty over the reused aspects.”
As it stands in Australia, incentives to reuse existing materials and keep existing buildings are limited.
Not enough focus is put on assessing the quality of buildings. Couple that with the relatively low price of new materials and it is easy to see how Australia has reached this throw-away mentality.
Dr Crawford says a whole-industry approach is needed to drive change.
“Responsibility must cut across all levels of the industry and government and even consumers,” he said.
“Once a design gets to site much of the waste has been locked in due to inefficient designs, redundant structures, use of non-standardised dimensions and components.
“Incentives to build smaller, maintain existing, minimise material production impacts, design to standardised material and product dimensions, design for disassembly are all key aspects that must be considered.”
This article is partnered content with Beyond Zero Emissions