Category: Asia Pacific

Source: The Conversation (Au and NZ) – By Nigel Bertram, Practice Professor of Architecture, Monash University

Investment in public housing is long overdue. But the current proposal to demolish all 44 of Melbourne’s social housing towers, relocate more than 10,000 residents and redevelop the sites is deeply flawed.

This blanket approach risks repeating the traumatic dislocation of vulnerable communities that happened when the towers were built more than 50 years ago. It also involves wasting money, energy and construction materials.

The state government says the old high-rises are being redeveloped to meet modern standards and house more people. But the decision to demolish and rebuild, rather than upgrade, has been challenged repeatedly.

I coauthored one of the most recent reports from concerned independent architects, urban designers and researchers. Together we argue retrofitting and upgrading existing housing stock, when combined with strategic new building, is technically feasible, cheaper and better for people and the planet.

At the same time, a class action lawsuit is awaiting a legal ruling on whether the government should be forced to release documents justifying demolition over retrofitting.

We know retaining and reusing existing structures saves energy and other resources, ultimately reducing greenhouse gas emissions. Across 44 buildings, this could also save around A$1.5 billion in construction costs.

Playing the numbers game

The federal government has set a national target to build 1.2 million homes by 2029. Victoria has a “bold” target to build 800,000 new homes over the next ten years. But how they go about meeting these targets matters too.

Melbourne’s housing commission towers are home to established communities, where connections between people have developed over a long period. This has immense social value.

The 44 towers also represent substantial embodied carbon. This is the carbon dioxide (CO₂) already emitted in extracting, manufacturing, transporting, installing and eventually disposing of existing concrete, bricks and other reusable materials.

Our analysis of one tower at Atherton Gardens estate revealed a potential saving of 16,000 tonnes of CO₂ through retrofitting. Multiplying this by 44 adds up to more than 700,000 tonnes – roughly equivalent to taking 150,000 cars off the road.

Taking tips from overseas

Overseas, similar postwar housing precincts have been updated and redeveloped in a more careful, considered way. Residents have even been able to stay in place while improvements are made. Such approaches incorporate a mix of renovation and retrofitting of existing buildings, combined with new infill and upgrades to public open spaces.

This approach integrates the precincts into the surrounding city and upgrades facilities to contemporary standards – without wholesale disruption and dislocation of the residents and their established communities.

It’s hard to know whether this work was considered during the decision-making process. The Victorian government and its housing agency Homes Victoria have so far refused to release the relevant reports or documents explaining their reasoning.

Such lack of transparency and consultation led to the launch of the class action. Residents at the Flemington and North Melbourne Estates have come together to argue their human rights were not considered when the decision to demolish their homes was made.

Two reports provide independent analysis

Filling the void, professional groups have undertaken two separate independent studies on a pro-bono basis. These reports analyse the different options based on the available information.

I helped compare three scenarios for a 20-storey tower at Atherton Gardens, Fitzroy. The research analysed two retrofit scenarios for the tower and compared these with a hypothetical equivalent new building.

We established the scope of building works required for each scenario. The team then measured capital cost, embodied carbon and carbon during operation for each case.

We found considerable savings can be made in capital costs (25–30%), embodied carbon (34–36%) and construction time (15–20%) through retrofitting, compared with constructing an equivalent new building.

When multiplied over 44 towers, these savings amount to about A$1.5 billion in raw construction value alone. This is without considering the additional costs of relocating existing residents, providing alternative accommodation during construction, or the social and health and wellbeing costs associated with long-term dislocation of communities.

A separate more detailed report on the Flemington Estate was released in October by charitable not-for-profit design and research practice OFFICE. Both reports independently arrived at very similar solutions for ways to address structural, fire and servicing upgrades.

Breaking down the barriers

Several reasons have been circulated as to why these high-rise towers are unsuitable for retrofitting. The two reports go through each in turn.

The towers are constructed from precast concrete slabs and internal walls are load-bearing. This makes refurbishment difficult, because the majority of walls cannot be moved. The buildings were also designed when the requirement to resist earthquakes was minimal.

A range of other technical hurdles, such as improving acoustic, thermal and fire separation and repairing degraded concrete, would also complicate upgrades. But none of these issues is insurmountable.

Both reports include strategies to address these issues, costed into the estimates. For example, the cost of strengthening to meet earthquake codes has been estimated as $1.73 million in Flemington and $3.85 million for Atherton Gardens. That’s around 3.7% of the total $105 million estimated construction cost for a single Atherton Gardens tower.

Exploring alternatives

The fact a building does not meet current regulatory standards is not in itself a reason for demolition. More than 80% of the city’s buildings would fail to meet these standards, including everything built in the 19th and 20th centuries. Our building codes recognise the value of existing structures and have provisions for renovation scenarios.

Retention and reuse of existing building fabric can achieve results surpassing current legislative standards while minimising waste, retaining the value of existing embodied carbon, and retaining the fabric, character and social memory of the city in the process.

Retrofitting can also avoid the mass displacement of existing residents, who would otherwise need to be accommodated during the construction phase. For instance, construction can allow refurbishment on a floor-by-floor basis, minimising relocation time for residents.

With the right design, skilled consultants, and genuine care for residents, it’s possible to overcome the barriers typically faced when reusing existing building stock.

I am grateful to Simon Robinson of OFFICE for his contributions to this article.

Read more:
Why knock down all public housing towers when retrofit can sometimes be better?

Nigel Bertram has previously received funding from the Australian Research Council

– ref. Demolition should be the last resort for Melbourne’s 44 public housing towers – retrofit and upgrade instead – https://theconversation.com/demolition-should-be-the-last-resort-for-melbournes-44-public-housing-towers-retrofit-and-upgrade-instead-246327