- freely available
Sustainability 2012, 4(10), 2707-2742; doi:10.3390/su4102707
Abstract: Prefabricated engineered solid wood panel construction systems can sequester and store CO2. Modular cross-laminated timber (CLT, also called cross-lam) panels form the basis of low-carbon, engineered construction systems using solid wood panels that can be used to build residential infill developments of 10 storeys or higher. Multi-apartment buildings of 4 to 10 storeys constructed entirely in timber, such as recently in Europe, are innovative, but their social and cultural acceptance in Australia and North America is at this stage still uncertain. Future commercial utilisation is only possible if there is a user acceptance. The author is part of a research team that aims to study two problems: first models of urban infill; then focus on how the use of the CLT systems can play an important role in facilitating a more livable city with better models of infill housing. Wood is an important contemporary building resource due to its low embodied energy and unique attributes. The potential of prefabricated engineered solid wood panel systems, such as CLT, as a sustainable building material and system is only just being realised around the globe. Since timber is one of the few materials that has the capacity to store carbon in large quantities over a long period of time, solid wood panel construction offers the opportunity of carbon engineering, to turn buildings into ‘carbon sinks’. Thus some of the historically negative environmental impact of urban development and construction can be turned around with CLT construction on brownfield sites.
1. Introduction and Problem Definition
Scientists are increasingly able to present empirical evidence about the environmental impact of global warming, including rising temperatures, soil erosion, and deforestation, falling water tables, ice melting, loss of biodiversity and animal habitat, threats to food security and the questionable use of grain to produce fuel for cars. Bold changes are needed to reduce carbon emissions; global warming also forces us to rethink the way we deal with population growth, urban development, carbon- and energy-intensive construction systems, linear and unsustainable material flows, consumption and urban life in general.
Most cities in the Asia-Pacific region are grappling with the challenges of urbanization and population growth. Alongside the concept of the ‘sustainable city’, the notion of the ‘liveable city’ has gained attention. The ‘sustainable city’ and the ‘liveable city’ are measured differently (for instance, a very energy-efficient city could still be an awful place to live). On the other hand, Australian cities are usually very liveable but not sustainable. So a step-by-step transformation of cities is required to increase their sustainability and peak oil resilience . There is scientific evidence that larger cities use resources more efficiently than smaller cities because of economy of scale; and that denser and well-interconnected cities generate less carbon per person [2,3,4,5,6].
As Australian cities grow inwards and become more compact, the cultural and social acceptance of urban infill and inner-city living becomes an issue. Urban infill and developments on brownfield sites mean cities become denser, so that residents can live in proximity to public transport, mixed-use precincts and their workplaces; it involves people moving from suburbs back to city centres and accepting multi-storey apartment buildings and townhouses. But therefore better models of infill housing are needed to ensure acceptance of inner-city living. An unattractive, overdeveloped example of inner-city apartment living in Sydney is shown in Figure 1.
Our linear economic system and current models of urbanization are based on the notion of continual urban and industrial growth, ever-expanding consumption, disposable products, resource depletion, waste creation and pollution [7,8]. Resources are extracted from the earth, refined, manufactured into parts and assembled into products, wh