The human race is growing cities to extraordinary and often perverse extremes. Many international cities are experiencing urban footprint growth that is coupled with near zero population growth. This phenomena results in excessive energy use in the construction and operation of our built environment ultimately resulting in burgeoning GHG emissions. So if we must build bigger cities, how can we take a more sustainable approach to building material selection and surface finishes that ameliorate and adapt to the impending climate nightmare?
There is no doubt that we are causing irreparable damage yet we will do worse if we despair. The aim must be to design human ecosystems for human benefit and ecological benefit. The impact from destruction of natural systems and the ecosystem services they provide and replacing them with our concrete and glass cities is an unsustainable microclimate in our cities. At the local level the thermal mass of our cities and their urban canyons heat up under extreme conditions, often holding nigh time temperatures over 5 degrees warmer that the suburbs. This impact is arguably complex yet easy to manage in the context of green architecture.
They are beginning to take action on the Urban Heat Island phenomena down at City of Melbourne Town Hall, employing the first ever Chief Resilience Officer. The target for this role is reported to aim at bringing the urban ambient temp down by 1% with an aim to reduce heat wave mortality by 30% (pers. coms). A bold a noble cause for all city dwelling humans out there.
The urban planners recently completed research indicating the humble trees in our streets are the primary mechanism to reduce the microclimate daytime ambient temperature by 1 degree in the public realm. This has convinced the design team to plan a distributed urban forest that will maximise shade, allow ventilation at night and employ water sensitive technologies to support trees and become our cities natural evaporative coolers.
For all our commercial and residential designers out there it is time to pitch in on the other side of the lot line. Cooler and less energy consumptive construction is the role of todays architect. The practice of biomimicry and the adoption of an ecosystem services philosophy will assist us to make our built form more like a tree. The benefits of this approach lie in careful external and internal material selection. The driving principles of reuse, reclaim restore and recycle offers a useful mantra when working in this space.
The principle of materials reuse on renovations is a worthy and rewarding cause yet an extraordinary under valued proposition. It is a bold endeavour to aim to repurpose materials on site from existing structures as they make way for the new building or renovation. To go further and up-cycle to an equal or better use than before is challenging yet rewarding if achieved. At the waste end of the cycle most material leaving site should be transported to recycling facilities ensuring very little materials are going to landfill. Another change in philosophy is to ensure material specification seeks recycled materials in new building forms.
In my experience designing and building a 7.5 star renovation in Cremorne Victoria explored adaptive reuse at every turn. The demolition began with sorting all materials for disposal to recycling facilities. We reused our 5 year old kitchen and wardrobes, harvested all reusable timber and kept the original front cottage with minimal modification. The principle of up-cycling often played out on the project. This is particularly true with the Oregon beams found in the lean-to of the old house. The most difficult element of this recovery for reuse was the storage while we waited for the day of reuse in a shade structure on the green roof. With demolition and storage behind us the task of sustainable material procurement began.
As the building emerged from the ground the slab was the first reuse experiment. A green concrete mix with additional reclaimed aggregate and cement replacement with slag from the iron ore smelting process. For interior fit out we went to great lengths on sourcing sustainable insulation and plaster. These choices were not always as they seemed. Insulation from recycled glass was easy to procure once we were aware it was a choice and interestingly much safer to install than traditional glasswool. Plaster is another challenge. Many products offered recycled content however it was equal to the extra 3mm of plaster in a commercial board and not available in domestic 10mm plaster at the time. As time goes on more recycled materials will enter the market, and the subsequent growth in choices will mean better outcomes for us all.
Our most extreme reuse occurred in the garden. During our construction we discovered that a research project had ended & 4 tonnes of green roof soil was heading for landfill. We weighed up the impact of a non-sterile soil and the potential hydrophobic nature of a soil that had been through the Black Saturday heat wave. Our philosophy on reuse was so strong we stepped in to divert the scoria substrate from waste to our roof. We rescued the packing sheets that came with our colourbond cladding and built the back fence entirely from waste.
Designers must also address the sustainability of materials used in the operation of our buildings. Designing to maximise reuse will provide a myriad of benefits for the occupier and environment. Water on our site is contained to less than 12 days a year of runoff, mimicking pre development conditions. The rainwater is reused more than once, passing through our roof garden, then ground level raingardens and ultimately rainwater tank. The tank double as a summer plunge pool and holding tank for irrigation and toilet flushing in winter. In this landscape water is the integrating element.
Adaptive reuse is a key principle in the way we have developed the Coolthinc philosophy on design through innovation and sustainability. It is clear that we need to be smarter about embodied energy and reduce the impact of our built environment on the local and global climate. The more we do to reimagine materials and turn to adaptive reuse the closer we will be to sustainable built environments.