Buildings design of the future must achieve two objectives. One, the building itself must be zero emission and two, it must be able to withstand the impact of climate change
Part –I: Buildings as a cause of climate change:
Let’s look at the first part, that of buildings being part of the problem and contributing to climate change.
No wonder that the International Panel on Climate Change states that the one key way to reduce the impact of climate change is to reduce high energy consumption and ultimately phase out CO2 emissions by the building sector
But that is easier said than done. What are the main stumbling blocks? Two findings in the UN report were:
1. Lack of awareness about low-cost energy-efficient measures among stakeholders which are proven to be more effective than high-cost technologies.
2. Lack of indicators to measure energy performance in buildings and most building occupants have little or no information about the energy saving potential of their building.
Making our buildings energy efficient
Closer home the story is the same. While Australia’s total contribution to the global CO2 emissions may be low, our per capita emission is quite high. And since buildings have been a significant contributor to this trend, the new buildings standards now require commercial and residential buildings to get an energy rating and meet minimum thermal requirements. Authorities have moved quickly to put in place energy performance indicators.
According to a document by Architecture 2030 that looks at design response to climate change, it is important to have design strategies that are low-cost or no-cost. This can get you 70-80% of the way there. For example, how you orient the building, shade the glass, incorporate day lighting and passive heating and cooling strategies, and the materials you use,can go a long way.
One of the key ways to reduce energy consumption is through the use of external wall cladding.
1. Trapped air between the cladding and interior wall offers natural insulation.
2. Material such as fiberglass batts or polystyrene foam, used as insulation under the external cladding can be very cost effective way of getting significant energy savings.
3. Installed correctly it can increase the R-value (thermal resistance) of a building significantly.
4. External cladding must meet the broader sustainability criteria – of product life cycle and meeting the economic and social aspirations of present and future generation – rather than the narrow green rating.
Part-II: Preparing our buildings for the impact of climate change:
Let’s look at the second and inevitable consequence of climate change – mitigating risk by adapting our buildings to cope. According to Australian government’s climate change document, by 2030 Australia can conservatively expect:
– Higher temperatures, leading to more heatwaves
– 25% more days of extreme heat and fire danger
– 20% more months of drought
– Increase in storm surges and severe weather events
– Sea levels will rise 15 cm.
– Flash flooding will be more frequent
Needless to say, we will be living in an environment more prone to extreme weather, and our buildings will bear the brunt. Insurance Australia Group calculated that a 25% increase in peak gusts causes 650 per cent increase in building damage. Architects and builders will need to develop skills to retrofit and design buildings aimed at protecting residents from these conditions. They are called “Adaptive Strategies”. The Australian government advises that future homes allow for modification to cope with climate change.
1. Ensure there is enough space on the property for additional water storage during drought spells.
2. Examine material suitability e.g. use of concrete floors, which have high thermal mass and recover well from floods.
3. Consider an exterior shape for the building that protects the structure from strong winds.
4. Relocate to higher ground to protect against flash flooding.
5. Insulate buildings with external wall cladding for greater energy efficiency to cope with extreme weather conditions.
6. Consider non-combustible materials for home exteriors if you are in a fire-prone region
Regardless of which side of the debate you take – supporter or skeptic, the fact is that regulators and insurance companies are preparing for climate change. And they will drive change in design and use of material in buildings.