Beat urban heat with light surfaces and green spaces

AFTER a hot, still day, parts of the city can be up to seven degrees hotter than the surrounding countryside. Dr Andrew Coutts, from Monash University’s Centre for Water Sensitive Cities, says a phenomenon known as the “urban heat island” effect means that built-up zones are often warmer than rural areas, particularly after dark.

“Urban areas store heat during the day and slowly release it during the night,” he says. “Meanwhile, rural areas can cool rapidly because soil and vegetation don’t store as much warmth.”

The urban heat island effect is present all year round, but it becomes a problem during the hotter months. “Without low temperatures during the night, we don’t get to recover from daily heat stress, especially when we have daytime temperatures in the high 30s and 40s,” Dr Coutts says.

Victoria’s chief health officer found that the heatwave preceding the Black Saturday fires might have contributed to 374 people’s deaths, more than double the number who perished in the fires. “Heat stress is a big concern for vulnerable people, such as the elderly, the really young, and those with pre-existing medical conditions,” he says.

Dr Coutts says the heat island effect has three main causes. Firstly, dense, impervious surfaces, such as asphalt and concrete, trap and store heat from the sun. “In urban areas we have these complex geometries, like street canyons, where heat gets absorbed by the walls, roads and roofs,” he says.

Secondly, human activities, such as driving cars and using air conditioners, generate waste heat. And finally, because cities have fewer trees and less vegetation, they receive natural less cooling from shade and evapotranspiration through foliage.

The effect creates a vicious cycle, in which prolonged heat makes people switch on their air conditioners, which leads to more waste heat. Likewise, higher temperatures predicted under climate change will mean extra air con – thereby increasing both the urban heat island and greenhouse gas emissions.

So how can we sink the heat island?

To keep your property cooler, plant trees in your garden and harvest stormwater for irrigation with tanks and rain gardens. Minimise hard surfaces such as solid concrete; opt for gravel paths or porous paving instead.

Also, lighter colours increase the “albedo”, or reflecting power of a surface, so when you restore or replace your roofing, follow the example of whitewashed Mediterranean cities. “If you paint your roof white, it increases the solar energy reflected away from the surface,” Dr Coutts says.

It’s also possible to buy dark-coloured paints that cut the heat absorbed by your roof. Ceramic-based, heat-reflective coatings are available from a number of businesses, including Astec Paints and Colorbond Steel. “They reflect solar radiation in the near-infrared spectrum,” he explains. “This means you can keep your traditional roof colours, and reduce your energy needs and the urban heat island as well.”

Dr Coutts and his colleagues are studying the cooling effect of street trees, as well as the relative benefits of green roofs and high albedo surfaces. He says the tactics we need for the city-at-large mirror the task at home: we must make our buildings and roads more reflective, plant more vegetation and harvest our stormwater. We also need better public transport to reduce waste heat from cars.

“It’s mainly about smart urban design,” Dr Coutts says. “We can have quite high density living without the impact of urban heat islands.”

Read this article at The Age online

Local walking groups are reclaiming the streets

HOW “walkable” is your neighbourhood? If it’s raining outside, you can find out by checking Walk Score, a website that measures “how easy it is to live a car-lite lifestyle” in your area. You might be surprised by what you find nearby.

The site was founded in the USA, but works in Australian cities too. Type in your address and it’ll rank your location from zero to one hundred, in a category from “car-dependent” through to “walker’s paradise”.

Dr Ben Rossiter, from Victoria Walks, says Walk Score is being used more often in real estate, especially in medium density suburbs.

“It gives people a really good idea of what is close by. The most highly walkable communities have a variety of services and facilities relevant to everyday life, all within walking distance – things like schools, shops, parks, cafes and movie theatres,” he says.

“Walking is becoming increasingly important to people when they’re deciding where they want to live. The choice might be more about having high walkability than it is about having a bigger backyard.”

Victoria Walks is a charity, funded by VicHealth, which promotes everyday walking. Among other initiatives, it will shortly launch an online mapping project in which residents upload their favourite routes, from strolls through hidden alleys to hikes in national parks.

“Walking goes beyond the act of getting physically active,” Rossiter says. “It creates safe, vibrant and connected communities. One of the key indicators of a healthy and sustainable neighbourhood is the number of kids walking to school.”

And, of course, more walking means less driving, and fewer carbon dioxide emissions. As the Walk Score website states, “Your feet are zero-pollution transportation machines”.

Rossiter says the first way to make your streets more walkable is to walk. “Step outside and say g’day to people while you do it. You could start an informal walking school bus with neighbours. We always like to see householders in their front yards too – grow vegetables there, so you can say hello when people go past.”

You can also form a Walkability Action Group, or join one in your area. (There are 16 existing groups listed on the Victoria Walks website.) Last year, a group in East Ivanhoe successfully lobbied local and state governments to install a pedestrian crossing next to the notorious Burke Road North roundabout.  

Another Walkability Action Group, Locomote, based on the Northern Bellarine Peninsula, has been working with local authorities to make their foreshore track usable for all-comers.

Locomote’s Patricia Crotty says “equity of access” is crucial, especially with an aging population in the region. “We’d love to see more people walking, but the footpath infrastructure isn’t great in these little towns. It’s a big issue for young parents with pushers too.”

Changes are afoot. In the centre of Portarlington, the council has widened the sidewalks and created a new town square.

“They’ve put in trees and places to sit, and restored the historic rotunda. It’s opened up the whole main street,” Crotty says. “People can wander around there in a way that wasn’t possible before, because traffic has been blocked off in the connecting street.

“Sustainable communities are places with gathering spots. They have to be safe and accessible, with the opportunity for people to come and sit in the main street and watch the world go by.”

Read this article at The Age online

On Neighbour Day this year, find new ways to say hi.

THIS summer, when four neighbours got fed up with their long lawns in Thornbury, in Melbourne’s north, they formed a mower collective.

One of the communal grass-cutters, Amy Brand, says it was just common sense. “There was a distinct lack of shareable lawnmowers in our area so we all threw in money to buy a mower that can become a community resource.”

She and her neighbours have signed onto The Sharehood, a website that encourages householders to meet and share with people nearby.

When you log in, you get to see the one hundred members who live nearest to you, and the things they’re happy to lend and borrow. You can also see a local noticeboard, where people within walking distance can post events and questions for each other.

The Sharehood began in Northcote in 2008, but there are now members throughout Australia and as far away as Cambridge, in the UK. The site is coordinated by a group of volunteers (including your Greener Homes columnist). To coincide with Neighbour Day, 27 March, The Sharehood is challenging householders to meet one new neighbour. The connection might prove to be good for both your tool shed and your well-being.

Ms Brand moved to Melbourne last year from Darwin. Getting to know people in her street has made her feel more at home. After mowing their lawns, she and her neighbours held a backyard movie night to celebrate.

“I’ve been a little sad at the lack of local community since I moved here,” she says. “I was spoilt for sharing and socialising in Darwin – it just seemed to grow and evolve so naturally. The Sharehood has been a reminder that community exists everywhere, but sometimes you just have to work a little harder to find it.”

The Sharehood is just one of many innovations boosting communities and green living. Lauren Anderson, from the consultancy CC Lab, says clothing exchanges, car-sharing and peer-to-peer renting are all examples of an emerging trend in “collaborative consumption”.

In the US, there are several neighbourliness and sharing websites, including NeighborGoods, Hey, Neighbor! and Share Some Sugar.

“These systems have created a revolution for sharing that allows us to minimise what we’re purchasing outright,” Ms Anderson says. “We have so much stuff in our possession that is sitting there idly.”

By making better use of the goods we have, we can buy fewer new products and reduce waste, energy and resource use.

Ms Anderson says that while some websites are based on free exchange, others make money for householders. Drive My Car Rentals and Rentoid are examples of “peer-to-peer” rental systems, where people trade with each other. Either way, she argues, collaborative consumption has a direct environmental benefit. “The technology is more of an enabler than an endpoint. It instantly matches haves and wants. People use it to participate in something in real life,” Ms Anderson says.

Landshare Australia is the perfect example – a local version of the popular UK website was launched in February. The website connects gardens with gardeners: enthusiastic vegie growers can find nearby landowners with space to spare.

“From a holistic perspective, sustainability is about people getting in touch with their neighbours, sharing common interests and realising the resources they can pool together,” she says. “Not everybody in the street needs a drill.”

Read this article at The Age online

If you’re building, plan for long-life, adaptable housing

NOT long after completing his architecture degree in 2007, Mathieu Gallois went on holiday to Lorne, on the Great Ocean Road. He stayed in a “big block box”, owned by a friend.

“I was struck how this home was contrary to everything we’d been taught about how to build a good sustainable house,” Mr Gallois recalls. “I was thinking, ‘What do you do with homes like this?’”

His answer is Reincarnated McMansion, a mix of architecture and art project, designed to challenge the way we think about our energy-sapping dwellings.

“Our proposal is to get a large unsustainable house, take it apart, and reuse the great majority of the materials to build two or three best-practice, zero-emission homes on the same site,” he explains.

The project also deconstructs the notion of a housing shortage in Australian cities. “Our new homes are three times as big as new homes in the UK,” he says. “There’s plenty of room for everybody. It’s just that we’re electing to live in bigger and bigger homes with fewer people in them.”

Now based in Sydney, Mr Gallois and his team hope to secure funding in the coming months. As well as making a point, the scheme should turn a profit: once constructed and displayed, the reincarnations will be sold.

While the designs will depend on the site, one key strategy will be to crush the old dwelling’s brick veneer and convert it into a type of rammed-earth interior wall, for thermal mass.

“All those materials we associate with suburbia – concrete, terracotta tiles and red bricks – will be visible in the Reincarnated McMansions,” he says.

The project will embrace a concept of green design championed by one of its members, architect Tone Wheeler, from Environa Studio. He’s coined the “three L’s” of sustainable building: long-life, loose-fit and low-impact.

In a conventional building, Mr Wheeler says, too little thought goes into the varied lifespans of component parts. Instead, we should consider buildings in two sections: the main frame, and the services and fittings.

“The long-life section is the structure of the building, the thing you can imagine lasting between one and two hundred years,” he says. The embodied energy of the structure doesn’t matter, so long as it is built to last.

The rest – the plumbing, wiring, sanitary-ware, heating and cooling, and interior – should be installed in a way that’s easy to adapt.

“You use a spanner, not a hammer,” Mr Wheeler says. “It’s not nailed and glued in place, but bolted so you can undo and remove it.”

Typically, bathrooms and kitchens are replaced every twenty years, and the renovations produce a lot of waste. “The wiring and plumbing is buried in the wall so you’ve got to rip off the plaster. You have to re-build the building.”

The third “L”, low-impact, relates to the fit-out. “We need to concentrate on using green materials for things like the carpet, paint and furniture. Think about the longevity, maintenance and renewal of those parts, and choose as good quality as you can find,” he says.

Mr Wheeler’s firm now designs houses so they can be split into two or three apartments in the future. “We need to recognise that buildings are continually updated, and design them in a way that can adapt to change,” he says.

Read this article at The Age online