20 Aug 2020

Why Brisbane needs good subtropical design for future buildings

Humidity, heat and a lack of shade are easy complaints to make against Brisbane but simple design guidelines for homes and buildings could change that for good.

If Brisbane is going to survive in increasingly sweltering temperatures, it needs to be compact, green, comfortable to live in and easy to get around.

The Queensland capital has a reputation for balmy outdoor living with timber houses, tropical parklands and a lazy river meandering through the suburbs.

But simmering humidity in summer months means walking around Brisbane is a hot, sticky and exposed experience, often without enough trees or shade to avoid the scorching sun.

Inner-city office towers bedecked in thick glass and snaking roads slathered in black asphalt, absorb and reflect heat, making it even hotter and more unappealing to step outside.

Instead of welcoming the climate in, we frequently shut it out - at home, on the road, and in the office. It's easy to fall back on obvious solutions like airconditioning, driving, or avoiding the outdoors altogether but those are high-energy, high-carbon measures that remove us from the outdoors.

The challenges lie in how the city is built.

The advocate

Architect and consultant Rosemary Kennedy has long championed well-designed cities with good, subtropical features.

Subtropical design welcomes the outdoors indoors, bringing breezes into buildings to cool them, capturing natural light and employing gardens and greenery to reduce heat.

"The subtropical climate is kind of a unique example of a hybrid climate," Dr Kennedy said.

"This climate combines tropical conditions part of the year, and temperate conditions for the other part of the year.

"That's the exciting part, really, for designers and architects."

The key is designing a building that can accommodate hot and humid conditions along with the cool, and even cold, weather south-east Queensland can face during winter.

Subtropical design, Dr Kennedy says, requires "deliberate and informed decision-making" during the design process, not a quick construct using typical design elements.

"The main condition that we're looking at in the tropics are heat and humidity and it's a huge factor that really comes into play," Dr Kennedy said.

"The requirement in terms of passive design is to ensure that there is air movement through a building to ease that feeling of humidity."

The feeling of air moving across the skin is what actually cools it, and that is a really strong, sensory element of a building being alive.

Dr Rosie Kennedy

Dr Kennedy says the focus must be on designing cross-ventilation, planning a building so it always has a breeze bringing fresh air through the central part of the house.

Instead, many homes and commercial buildings look inward, using airconditioning to moderate the indoor temperature and paying little attention to the context of the land and environment they are built on.

"Some people might think that it doesn't apply to them but the principles of good design can benefit all types of buildings," Dr Kennedy said.

Shey says the concepts of subtropical design apply not just to individual buildings but entire suburban layouts and how that can affect the overall living experience.

The developer

In the city centre, commercial developers are increasingly altering the traditional office tower block, moving away from walls of glass, steel and concrete.

Large-scale tower developments are incorporating levels open to the elements – rooftop or mid-level gardens, water features, and even hanging gardens draped down sheer walls – relying on cross-ventilation and the position of the sun to heat and cool appropriately.

Last year Brisbane City Council issued a subtropical design standards document – 'Buildings that Breathe' – a non-enforceable guideline for developers on design elements friendly to south-east Queensland's climate.

Brisbane developer Aria Property has made a name for itawld designing and constructing sustainable and green-focused developments.

Its latest proposal, still before the council for approval, is a 30-storey green residential tower swathed in trees and plants – so much so, it will be more than 290 per cent covered in greenery.

Aria's Michael Hurley has been shepherding the "Urban Forest" from the start, describing it as a natural progression for the property group to take on such an ambitious project.

"We really felt that this site in particular had a lot of attributes that led to it, one of which we've been talking for a very long time about, a green spine connection between South Bank and Musgrave Park," Hurley said.

"We want to upgrade the whole of Glenelg Street and turn it into a world-class green spine, similar to what Aria has already done with Fish Lane."

Hurley says the council's subtropical design principles are a strong step in the right direction for designing a living, breathing Brisbane, and the "Urban Forest" meets all of them.

The tower design incorporates large parkland at the base, collects its own water for irrigation, and will have sizeable apartment balconies for shade and space.

The design process brought up hundreds of questions: how would the building cope with wind load? How would they irrigate the 1000 trees on the building's skin? How would it look and feel?

The price isn't cheap, but Hurley says Aria's focus is on a lasting and sustainable legacy, building homes that will be cheaper to run and enjoyable to live in.

"The long-term trend is infill development," Hurley said.

"You can either bulldoze a whole heap of koala habitat to put in a masterplanned housing community, or you can take a 1280-square-metre site, go vertical, and have the same number of people occupy a small piece of land.

"We know that half the population is moving to infill development, how can you make that built form, that apartment ... give them all the things they would get with a beautiful orientated Queenslander on a 500-square-metre block?"

The urban planner

For urban planners, looking at the wholescale development of a city and its surrounds, subtropical design principles come with their own set of challenges.

For instance, if we need more infill development to prevent a city sprawl consuming vast tracts of land, then we need to ensure the new built environment is compact and easy to access and navigate.

Towering skyscrapers need more non-biodegradable materials such as concrete and steel, more energy to power elevators and lifts and have greater cooling and heating needs.

University of Queensland lecturer in urban planning Dorina Pojani says Brisbane needs compact infill development with short, well-connected and shaded paths, so we aren't tempted to fall back to airconditioned cars.

Dr Pojani says constructing 30-to-40-storey towers, as has been increasingly popular in the city centre, is particularly energy intensive.

"It's quite different to have a Queenslander made of wood ... if you want to remove a Queenslander, one day you can recycle it," Dr Pojani said.

"But once you put up a 30-storey, 40-storey tower, that requires very strong structural support."

The planning expert says there needs to be a balance between infill and the height of new developments, with more research needed into Brisbane's ideal tower height.

The other challenge, she says, is and excessive focus on individual buildings in the council guidelines.

"Urban design needs to be ... maybe not all the way to the suburb level, but to the block level - how I want to design a whole block rather than just going by individual building," she said.

The architects

Domestic houses are harking back more to open-plan living, linking inside and outside with wide windows and balconies, angled to catch cross-breezes and protect dwellers from the harsh summer sun while welcoming in warm winter rays.

Architects Sonia Graham and Chris Bligh, of Bligh Graham Architects in Samford, spend most of their time redeveloping poorly designed houses.

Real information and education on what subtropical design is and why it is important is critical, they say.

The cost of building a properly designed home rather than a "cookie-cutter" masterbuilt design on a 500-square-metre block is not unreachable.

"If the house isn't designed well, then the buildings become very unpleasant to live in, or they're dependent on air conditioning for heating and cooling," Graham said.

"Sadly it's a lot of the lower socioeconomic places where there is not that time given to good design, which is essential for all buildings."

Living in an "airconditioned box", Bligh says, is unnecessary if people planning a home take some time to think carefully, and if regulation supports rather than punishes people who choose a different design.

"Once you have a building that performs well passively, it also has all these other benefits, psychologically and emotionally," Bligh said.

"How you connect ... and how you experience the world through all your senses, rather than just being a hermetically sealed box with air conditioning on."

Having a home that is more open to elements returns to the more community-focused lifestyle of old Brisbane Queenslanders, the architect say, with people on their verandahs chatting to neighbours and passers-by rather than tucked away behind doors.

A good home in a well-designed suburban environment, with shady street trees and accessible connections, can mean the world of difference.

Bligh and Graham are pushing further into the subtropical design space, seeking to educate more people on the benefits of building a well-designed home.

"We're in a fantastic climate ... when you look at it holistically, we have the potential for amazing environments, but sadly it doesn't always happen from lack of well-thought-out design," Graham said.

"It doesn't necessarily have to be a lot more expensive.

"The dollars aren't necessarily going to be that much more, but the long-term running of the house – and not many people think about this – is a huge difference."

SOURCE: https://www.brisbanetimes.com.au/national/queensland/why-brisbane-needs-good-subtropical-design-for-future-buildings-20200821-p55nxb.html

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