ESD - Just Another TLA?
By James Mackness.
Not every building can use timber construction,
but that possibility is now closer than ever.
|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.
|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.
|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?