How to build for the tropics – JCU and Tropical Building Network team up
Willow Aliento | 4 September 2014
James Cook University and the Tropical Green Building Network have teamed up to create an online resource that showcases which sustainable building initiatives work best in the tropics. And with more than half of the world’s population expected to be living in the tropical zones by 2020, the developers of the Tropical Design Case Studies say there is growing opportunity for this kind of know-how to foster increasing opportunities for local experts in the markets of South East Asia, Papua New Guinea and the Pacific Islands.
The major issue for green building in the tropics is that the building code and rating systems have been developed for the temperate southern states, JCU urban geographer Dr Lisa Law says, but these solutions often do not translate well in hot, humid climates like Cairns and Darwin.
The website presents examples of buildings that suit their context and deliver on energy efficiency, ventilation and thermal comfort, ranging from small homes to large commercial and civil projects. Each case study is accompanied by enormous detail on the project’s design, materials and energy use, as well as comments from the owners and users.
The JCU Sustainability Fund provided the funding for the project, and individuals part of the case studies contributed on a pro-bono basis.
“When you look at the building codes and green tools, there is room to reflect on how they work across different climate zones,” Dr Law told The Fifth Estate.
“We need to be developing our own repertoire for what constitutes good, green, tropical places. We need to have the right rating tools, policy, planning and building codes. We are not Canberra, and we are not Singapore.”
Some of the issues she identifies include the selection of appropriate, regionally endemic vegetation for green spaces to cool the city down. At the individual home level, the issue becomes not just one of species, but also an issue of space, as while the council guidelines recommend planting trees for their cooling benefits, the footprint of dwellings on lots is in many cases not leaving sufficient room to plant them.
Another consideration relating to urban planning is designing streets with an orientation and alignment that can maximise the benefit of breezes, rather than designing in cul-de-sacs and “curly” streets.
Dr Law says the language of tropical urbanism is beginning to develop, and that work is being undertaken to engage with industry and government on a range of issues, including masterplanning, water sensitive urban design appropriate for the Far North Queensland region and public transport.
Opportunities for Asian collaboration
Engineer Emma Thirkell, co-initiator of the case studies project and facilitator of the Tropical Green Building Network, says buildings that ensure people are experiencing the climate – rather than living and working in something designed like an esky – are the key to becoming acclimatised. And unless they become acclimatised, people simply will not thrive in the tropics.
Ms Thirkell gave a presentation about the case studies to the World Green Building Council in Indonesia this year, while participating in an Austrade trade mission. Cairns Regional Council sponsored her trip, as increasingly there is a recognition that the geographical closeness between Cairns and places including Indonesia and PNG is a driver of growing opportunities for Cairns-based consultants and building specialists.
“Where people in South East Asia find value is in our knowledge, so we are able to work with them to deliver buildings with much better quality, and they also value our experience in plugging in the new building technologies,” Ms Thirkell says.
Other strengths in the local consulting sector have developed because of the lack of infrastructure for electricity and water across large parts of Australia’s far north. Ms Thirkell says there are engineers who have developed high levels of renewable energy expertise through creating solutions for off-grid communities, and also substantial expertise in the area of water treatment and waste water management.
Both of these are skill areas in high demand for nations such as PNG and Indonesia, where growth and development issues are creating pressing needs for sustainable solutions, and Ms Thirkell says Australian consultants with tropical experience are well-placed to assist.
While it may be close to these offshore neighbours, Cairns is remote from Brisbane and other Australian sources of materials and expertise. This itself becomes a driver for a style of green building that suits resource-limited communities.
“In this region, you’ve got to come from a low base and be very careful of energy and materials, because it is such a distance to bring them from,” Ms Thirkell says.
“There are also issues with building systems, in many cases, people have to fly an HVAC engineer up from Brisbane when things break.
“Passive design is number one.”
Timber suits the North
Timber is a material that suits the climatic context, Ms Thirkell says. Unlike concrete block, which has a thermal lag because it absorbs heat, timber cools down quickly. Research by the CSIRO cyclone materials testing facility has shown that lightweight materials, including timber, can also meet the standards for cyclone ratings.
However, Ms Thirkell says, there are many new green technologies and materials that have not sought cyclone testing as the Cairns market is so remote, and without the cyclone-rating in place, they simply do not meet the requirements of the Building Code for the area.
Multiple stakeholders the key to success
Developing the language and documenting the expertise, materials and methodologies around green building for the tropics for the case studies, and for the recently completed Tropical Expertise resources at the Greenbuild website, has involved a multi-stakeholder working group. This group included a Green Building Council of Australia-accredited architect, representation from the Planning Institute of Australia, the Building Designers Association of Queensland, engineers and representative from industry associations.
“Every case study represents a team of people who are expert at what they do, and owners who revel in these buildings and really enjoy life in the tropics,” Ms Thirkell says. “They have all been very generous in sharing their expertise and their experiences.”
Some of the key passive design measures Ms Thirkell says are vital for the tropics include:
- Do everything possible to keep the sun from hitting the walls and windows of the building, for example, add wide eaves
- Incorporate breezeways through dwellings, and orient the building to maximise the benefit of breezes for passive ventilation and cooling
- Choose lightweight materials that do not retain heat;
- Design for gutters and plumbing that can accommodate the monsoon season
- Be aware glues and caulkings can deteriorate faster
- Ventilate naturally and well to prevent mould