ESD - Just Another TLA?
By James Mackness.
Not every building can use timber construction,
but that possibility is now closer than ever.
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| Green Wall, Docklands - Melbourne. (Source: Mackness, J, 2017). |
Ecologically Sustainable Development (or Environmentally
Sustainable Design, depending on your preference for a good old three letter
acronym [TLA]) is now well-embedded into planning lingo. Despite the
Environmentally Sustainable Design Statements we’re
typically required to produce as part of the planning process, the question
arises to whether what we’re
delivering is really environmentally sustainable?
Our predominant building materials such as concrete, steel, brick, and glass are
generally at the ‘higher end’ of the scale for embodied energy.
Also, unlike timber, these materials don’t grow
on trees. They are finite resources, which drive up construction costs as scarcity
increases.
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| Relative embodies energy of building materials. (Source: Australian Government, 2013) |
An alternative way to provide for more sustainable buildings
is the inclusion of green infrastructure. Green roofs, walls, and façades reduce the energy demands of
buildings for heating and cooling. Green infrastructure has the added benefit
of being truly multifunctional. A green roof not only lowers the energy use of
the building, but it also reduces the urban ‘heat
island’ effect of the city, provides
habitat for nature, and provides a more aesthetically pleasing view than that of a
traditional built rooftop would offer.
Despite views to the contrary, green roofs aren’t incompatible with providing energy
generation via solar panels. In fact, photovoltaic panels can benefit from
being on a green roof by virtue of a cooler microclimate, thus increasing the
efficiency of energy generation. The green roof also benefits by virtue of the
shade provided by the panels and condensation runoff, which can improve the
biodiversity of the roof.
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| Green roof and photovoltaic cells on one of Transport for London’s buildings, UK. (Source: Living Roofs, 2017) |
Although maintenance is required for the green roof, there
can be a reduction in maintenance requirements in the long run as the living
material protects the roof structure from UV radiation. This aspect is of
course more attractive to institutional investors and their long-term view of
property assets rather than developers looking for an immediate return on
investment.
So with all these great benefits, why aren’t we building more of them? With the
introduction of the Better Apartments Design Standards (BADS) to the Victorian Planning
Scheme, maybe we will. Standard D10 states:
Development
should provide the deep soil areas and canopy trees. If the development cannot
provide the deep soil areas and canopy trees specified…an equivalent canopy
cover should be achieved by providing either:
- Canopy trees or climbers (over a pergola) with planter pits sized appropriately for the mature tree soil volume requirements.
- Vegetated planters, green roofs or green facades
It will be interesting to see how this requirement will
playout at VCAT, where many development ‘rules
of thumb’ are often determined. Will
the expectation of green infrastructure in lieu of deep soil zones be on a
one-for-one basis? Deep soil zones provide greater opportunities for stormwater
retention, planting, and the ability to recharge groundwater, so should a
greater ratio be applied?
Further reading:
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