Shiny new high-performance buildings are fabulous, but upgrading an existing building has some fundamental sustainability advantages. The Fifth Estate turned to experts from engineering, architecture and development to find out the opportunities for refurbishing or repurposing older buildings, and the key factors for success.
No building is “beyond hope” for a second life, according to Irwinconsult managing director Phil Gardiner.
There is a financial and environmental case for refurbishment. Gardiner says for most sound buildings it is more economical to refurbish than demolish and start again. The exception is if demolition allows for a larger development.
There are some caveats to do with building quality too. Asbestos is a big issue to deal with, he says, and if the building is in poor structural condition remediation can be costly.
“Structurally it helps if the building has good load capacity.”
It also helps if the building structure makes it easier to create new openings for interconnecting stairs and other contemporary design elements.
Office buildings from the 1970s and earlier usually have smaller column grids and lower floor capacity, while older industrial and storage buildings are sometimes better due to their stronger bones.
Some of the projects the firm has worked on where structural works were carried out include the University of Melbourne Old Quadrangle redevelopment. The design included strengthening works to significantly improve the existing structure and ensure that the building – the oldest on the University’s Parkville Campus– performs for many years into the future.
Irwinconsult director Dean Whiteley says that ’80s and ’90s glass towers are most difficult to refurbish due to the extent of glass, as the glazing does not comply with latest energy requirements.
“Introduction of spandrel panels can help, plus adding high-performance films to glass.”
In terms of services, increasing outside air in existing buildings can be a challenge, especially when existing ductwork is to be retained.
“Demand control ventilation with CO2 sensors could be an answer, plus energy recovery units. Existing ductwork, if retained, also needs to be cleaned thoroughly.”
Whiteley says it is important to look at building fabric.
Sometimes thermal mass is sufficient, and adding insulation to the walls is not required.
“[It is] always important to improve air tightness, especially in old buildings.”
The services angle can be tricky. Whiteley says that often buildings 30 years old or more will require complete replacement of building services due to their condition.
However, even if services need to be fully replaced, significant cost saving can be achieved through re-use of the structure and façade.
“A cost effective services design should endeavour to minimise impact on structure and façade.”
Significant cost impacts in terms of the structure and facade that services can generate include the installation of additional lifts, additional plant loadings, services penetrations through the structure and facade, and the sealing of leaky buildings.
At 276 Flinders Street, works to refurbish and modernise a 40-year-old building included conversion of the podium levels from commercial to retail. In addition to introducing escalators, the project involved an upgrade of the major base building infrastructure while the building remained operational.
“The other issue that needs to be considered if proposing to maintain building services systems, is the change in code compliance requirements,” Whiteley says.
“If refurbishing over 50 per cent of the building the entire building services needs to be upgraded to current code requirements.
“This can have a significant impact on mechanical plant and equipment due to changes in outside air ventilation rates and energy performance requirements.”
Fire systems can also be impacted by the latest code requirements.
Another important consideration when a building is having a change of use is that different usages often mean different code requirements. For example, there is a difference between code requirements for multi-residential buildings and commercial office buildings.
Whiteley says client design criteria such as a change in occupancy rates as part of a change of use refurbishment can also have a significant impact on the services design.
One of Melbourne’s iconic adaptive re-use projects, Hero Apartments, highlights how the different elements of structural and services come together.
Completed in 2001, the building was originally the Russell Street telephone exchange and post office.
Irwinconsult provided full structural engineering design services from concept to completion. The initiatives included reduced strengthening requirements for the existing columns and pad footings in the existing buildings.
Steel-framed construction was recommended for the new building levels to enable the use of short spans and thin slabs. This minimised the mass of the new structure and enabled five new upper floors and two new mezzanine levels to be added to the existing nine-storey structure.
Another adaptive re-use project was the La Trobe University Donald Whitehead Building.
Originally constructed in the 1960s, the new incarnation designed by architects Hayball entailed first stripping it back to the bare structure and modifying it extensively in order to meet both the design intent and current BCA requirements.
Designing for a new life
SJB architects Gabby Suhr
and Sevda Cetin told The Fifth Estate that when a building is being designed for reuse, retaining as much as possible is the starting point.
In terms of what makes for “good bones” in a building, Suhr says it is not just a matter of the physical structure.
For the Willoughby Incinerator project, which saw a heritage incinerator building designed by Walter Burley Griffin repurposed into a council-owned community hub and gallery space, the history of the building was part of its bones.
“The story is an important part,” Suhr says. “Bones are not necessarily a physical thing.”
Re-use is about sharing that history and keeping the building alive and in use.
Suhr says SJB started with a passive design approach, which required the architects to “push the creativity” to get natural light and air into the interior spaces. One of the fundamental questions was to what degree the spaces would need airconditioning, she says.
In terms of the lower levels, which are built into the side of a cliff, the ambient temperature is naturally cooler, reducing the need for mechanical cooling.
Creating an exhaust system for the planned cafe was a challenge, and the design decision was made to direct that through the roof.
Finding the right experts is also important. The incinerator’s existing windows had steel frames and were worth re-using due to their character. A proper steelworker had to be sourced for the work of refurbishing them, Suhr says.
Cetin was project architect on 100 Harris Street in Pyrmont, Sydney, which saw a heritage wool store repurposed as a contemporary commercial office knowledge hub, tech hub and co-working spaces.
The key positive elements of the building that could be retained included columns and beams of heavy timbers, and a layout that lent itself to the types of tenants it aimed to attract.
Structure, space and building integrity are the three key factors for any re-use project, she says.
100 Harris had an existing saw-toothed roof that provided a major win for passive design, as glazing in the roof enabled light into the space. Creating an atrium within the building to utilise that light meant it could penetrate deep into the floor plates.
The building was “never meant to be airconditioned,” Cetin says.
Louvres in the sawtooth roof instead provide natural air.
In terms of modern HVAC introduced during the redevelopment, Cetin says the system has been zoned so units are only turned on when required by building users.
In general, she says it is possible to “push the tolerance of human expectation in those spaces”.
While an ambient temperature between 22-25°C is generally the goal for commercial spaces, humans can tolerate 27-28°C temperatures so long as there is some air movement.
One of the structural challenges with the project was that the client was aiming for an occupant density of one person per six square metres, when the BCA deemed to satisfy requirement is one person per 10 sq m. That meant to achieve compliance, sufficient emergency exits had to be created to ensure fire safety, and this meant cutting holes in the building structure.
“A certain amount of gymnastics was required,” Cetin says.
Overall, before a project team can look at ways to make an existing building a high-performing one, it is important to look at the concrete, Suhr says.
“Concrete cancer can be cost prohibitive.”
But if a team can “get the bones right”, clever design can resolve challenges such as designing ductwork in a way that gets around difficulties modifying the existing structure.
Making windows operable may not be so easy though. Cetin says it helps to design for operable windows in the first place, as it can be a major budget item to replace non-operable glazing across a facade.
“Obviously it is cheaper and easier to condition those spaces.”
There are some eras that really shine in terms of passive design. Suhr says the Nicholas Building in Swanston Street, Melbourne, for example, which was designed and built in the 1920s, features large casement windows.
“The spaces were designed in a much more passive way,” she says. The spaces also had high ceilings and a large level of natural light.
“They start with a level of comfort where many modern buildings don’t.”
Buildings designed between the 1950s and 1970s, for example, had an engineering-led approach to occupant comfort, where the 22-25°C indoor environment reliant on mechanical plant became business as usual.
Now it has come full circle, Suhr says. People have realised that artificially controlling the environment has an impact on how we work – and that passive solutions can be beneficial.
“We have become more sustainability conscious.”
What a REIT looks for
Forza Capital director Adam Murchie says when looking at a building’s potential for upgrade or reuse, there are a few key
considerations.
They include the existing building floor plate and structure, whether it has reasonable natural light to the interiors and whether the floor plate lends itself to conversion into contemporary open layouts.
A big part is also the location of the asset, and what type of tenants that location will appeal to.
“Some buildings are like shags on a rock with nothing around them,” he says.
A lack of local transport and amenity is a big no, as having support services around matters to most tenants because these things matter to their staff.
“Part of the sustainability equation is being somewhere people want to be.”
The nitty gritty analysis of potential includes understanding what the process will be for cutting lightwells and breaking up floor plates.
“You often just need smart people – smart architects and smart designers,” Murchie says.
He says there are “no particular eras” of building that are better or worse in terms of potential.
Two of its redevelopment projects are good examples of this adaptable outlook.
One was the redevelopment of the former Carlton United Breweries laboratory into a high-performing headquarters for the Victorian Environment Protection Authority.
Murchie says the building was taken on as an asset that was “vacant and full of pigeon poo”.
An old Hoyts Cinema was redeveloped into a commercial office asset. The design retained the curved cinema floorplate, adding flat internal walls and using the area between those and the curved walls as the plenum for the airconditioning.
This also got around the issue of the building having post-tensioned slabs, so it was not possible to cut into them.
In heritage buildings, Murchie says the goal is to pick buildings with good bones, and then “work the assets hard”.
This includes upgrading existing services. One of the more daunting elements in this regard is chillers. They are expensive to replace, but they can also be a “real energy vortex” if not up to scratch.
HVAC is overall a “hideous expense” to upgrade or refit.
There are some potential easy wins. Murchie says that when it comes to building services, “a lot of things over the years might have been bastardised.”
The quick fix is to tune it all back to how it is meant to run.
Most buildings also have some form of BMS in place, and this can be upgraded and new meter and measurement points installed.
“Our best value comes from getting the right infrastructure in and having smart people to tune and operate that.”