Ventilation research on Australian residential construction

This paper applies established testing methods used to discover the ventilation performance of various residential building envelope construction in Australia. Under the definition of 'ventilation performance' we imply the building envelope leakage (or infiltration) the living space air change rates, the volumetric flow rates and the pathways of air flow between subfloor, room volume and roof spaces. All of the methods applied and discussed here are on-site, evidencebased performance of actual structures as tested by the Mobile Architecture & Built Environment Laboratory and Air Barrier Technologies.

Use of renewable building materials in residential construction : a review

The development of mass-produced environmentally-benign housing is one of the critical factors in the transition to global sustainability. Such housing will need to be constructed from renewable and/or recycled materials, be conditioned using minimal or no non—renewable energy, and be affordable. The universal need for such built environment resource stewardship is urgent. In developing countries, the requirement is to shelter growing populations, and in industrialised countries, there is a need for an alternative to the current resource and nergy-intensive material usage in housing. While there are some good surveys of building materials made from renewable resources, such as the BEDP Environment Design Guide Pro 11 by Gelder (2002), there does not appear to be a comprehensive database of these materials linked to abundant and reliable supply. This paper reviews the current availability and potential usage of renewable materials applicable to Australian mainstream residential construction. It concludes that the current state of publicly available information is dispersed and embedded in multiple sources with variance in detail, incomplete access and uncertain comparison across the sources.

Ventilation research on Australian residential construction

This paper applies established and new testing methods to discover the ventilation performance of various residential building envelope constructions in Australia. Under the definition of 'ventilation performance' we imply the building envelope leakage (or infiltration) of the living space air change rates, the volumetric flow rates and the pathways of air flow between subfloor, living and roof spaces. All of the methods applied and discussed here are on-site, evidence-based performance of actual structures as tested by the Mobile Architecture and Built Environment Laboratory and Air Barrier Technologies. The testing processes primarily involve the Tracer Gas Decay Method (TGDM) and rhe fan pressurisation method (FPM a.k.a 'blower door'). All the measurements are performed with respect to the external wind speed and direction as well as the typical weather parameters. This paper discusses the differences and similarities of both testing methods as well as several other testing procedures that can inform the researcher on air leakage pathways. Findings of a simultaneous TGDM and FPM air leakage rate comparison are also encountered in this paper. One of the most informative testing methods, is the application of three different tracer gasses introduced into different spaces (subfloor, living and roof) to discover pathways of air flow within residential construction.

Analysing the relationship between new housing supply and residential construction costs with the regional heterogeneities

New housing supply in Australia has been experiencing a low rate of increase in conjunction with a dramatic increase in residential construction costs since the 1990s. This study aims to estimate the relationship between new housing supply and residential construction costs with the regional heterogeneities. Based on a panel error correction model, it can be identified that there is a causal link as well as a significant correlation between new housing supply and construction costs in the Australian sub-national housing construction markets. The model developed in this research assists policy makers to better understand the nature of the supply side of the housing sector and then enact appropriate policies to improve the new housing supply in Australia.

New housing supply and residential construction costs in Australia : a panel ECM approach

The supply of new housing in Australia has been experiencing a low increase rate since the 1990s in conjunction with an increasingly strong housing demand. On the contrary, residential construction costs across Australia?s states maintained dramatic increases simultaneously. Economic theory suggests that new housing supply is correlated to the costs of residential constructions. However, few empirical studies have focused on examining this relationship for Australian housing markets. To comprehensively investigate the relationship between the supply of new housing and residential construction costs a function for new housing supply considering the effects of regional heterogeneities is introduced in this study. By estimating a panel error correction model (ECM) applicable for quantifying the correlation with regional heterogeneities, this research identifies that a causal link and a strong correlation exist in between new housing supply and residential construction costs in Australia.

Increasing the level of sustainability via off-site production : a study of the residential construction sector in China

Even though the use of off-site production in the construction process for residential buildings is seen as a viable means of increasing the level of sustainability with respects to its significant economic, environmental and social contributions, there have been very few studies to-date into off-site construction within the context of developing countries where the places have crucial demands for accommodations. Accordingly this research involves the rapidly growing developing nation, China, as a representative developing country with the objective to investigate the current status of off-site practices in the urban residential construction sector. This paper also examines the factors affecting demand for and potential barriers against a wider uptake of off-site technologies in China. The findings provide a rare insight into off-site construction in China’s housing industry and this information will be transferable to other developing countries. This study also contributes to a broader understanding about the off-site construction in developing from an international perspective.

Height and construction costs of residential buildings in Hong Kong and Shanghai

A widely recognised theme of construction economics suggests that the cost of construction per square metre increases as building height rises. However, after many years, research conducted regarding the height and cost issue have established a classic relationship between those two, well known as a U-shaped curve. This paper describes the study of height-cost relationship of high-rise residential buildings in Shanghai and Hong Kong. Initial findings indicated that the curved relationships of height-cost of residential buildings in Shanghai and Hong Kong exhibit different profiles. The differences suggest that, Hong Kong contractors have more expertise in multi-storey and high-rise construction than contractors in Shanghai. The dissimilarities also imply that different sets of criteria should be applied in the judgement of height affects cost in different locations. Many factors could be contributors, such as the history and experience in constructing residential high-rise buildings, location, linkage and relationships to the neighbourhood provinces, design and construction regulations, and government policy on residential construction.

The Australian construction linkages in the 1990s

Abstract: During the 1990s, the construction sector played an important role with its growing contributions to the gross national product, gross domestic product and employment in the Australian economy. Using the newly released 1998-99 input-output table and four previously published tables by the Australian Bureau of Statistics, this paper aims to measure the sectoral linkages of the Australian construction sector in the 1990s in relation to other industrial countries. Results describe the increase in construction volume was mainly due to the increase in governmental and non-residential construction expenditures and lagging construction technology. The technical level of the non-residential construction sub-sector was a drag to the total construction, while the non-residential construction sub-sector presented a stronger economic push than that of the residential construction sub-sector. In the 1990s, the inputs and outputs' components of the construction sector were stable. The linkages of the Australian construction sector are discussed from an international point of view.

A comprehensive framework for assessing the life cycle energy of building construction assemblies

Environmental decision making during the building design process has typically focused on improvements to operational efficiencies. Improvements to thermal performance and efficiency of appliances and systems within buildings both aim to reduce resource consumption and environmental impacts associated with the operation of buildings. Significant reductions in building energy and water consumption are possible; however often the impacts occurring across the other stages of a building‘s life are not considered or are seen as insignificant in comparison.

Previous research shows that embodied impacts (raw material extraction, processing, manufacture, transportation and construction) can be as significant as those related to building operation. There is, however, limited consistent and comprehensive information available for building designers to make informed decisions in this area. Often the information that is available is from disparate sources, which makes comparison of alternative solutions unreliable and risky. lt is also important that decisions are made from a life cycle perspective, ensuring that strategies to reduce environmental impacts from one life cycle stage do not come at the expense of an increase in overall life cycle impacts

A consistent and comprehensive framework for assessing and specifying building assemblies for enhanced environmental outcomes does not currently exist. This paper presents the initial findings of a project that aims to establish a database of the life cycle energy requirements of a broad range of construction assemblies, based on a comprehensive assessment framework. Life cycle energy requirements have been calculated for eight standard residential construction assemblies integrating an innovative embodied energy assessment technique with thermal performance simulation modelling and ranked according to their performance.

The potential to reduce the embodied energy in construction through the use of renewable materials

The threat of dangerous levels of global warming demand that we significantly reduce carbon emissions over the coming decades. Globally, carbon emissions from all energy end-uses in buildings in 2004 were estimated to be 8.6 Gt CO2 or almost one quarter of total CO2 emissions (IPCC 2007). In Australia, nearly ten per cent of greenhouse gases come from the residential sector (DCCEE 2012). However, it is not merely the operation of the buildings that contributes to their CO2 emissions, but the energy used over their entire life cycle. Research has demonstrated that the embodied energy of the construction materials used in a building can sometimes equal the operational energy over the building’s entire lifetime (Crawford 2011). Therefore the materials used in construction need to be carefully considered. Conventional building materials not only represent high levels of embodied energy but also use resources that are finite and are being depleted. Renewable building materials are those materials that can be regenerated quickly enough to remove the threat of depletion and in theory their production could be carbon-neutral. To assess the potential for renewable building materials to reduce the embodied energy content of residential construction, the embodied energy of a small residential building has been determined. Wherever possible, the conventional construction materials were then replaced by commercially-available renewable building materials. The embodied energy of the building was then recalculated. The analysis showed that the embodied energy of the building could be reduced from 7.5 GJ per m2 to 5.4 GJ per m2 i.e. by 28%. The commercial availability of renewable materials, however, was a limiting factor and indicated that the industry is not yet well positioned to embrace this strategy to reduce embodied energy of construction. While some conventional building materials could readily be replaced, in many instances a renewable substitute could not be found.

The effects of the late 2000s global financial crisis on Australia's construction demand

An accurate measurement of the impacts of external shocks on construction demand will enable construction industry policymakers and developers to make allowances for future occurrences and advance the construction industry in a sustainable manner. This paper aims to measurethe dynamic effects of the late 2000s global financial crisis on the level of demand in the Australian construction industry. The vector error correction (VEC) model with intervention indicators is employed to estimate the external impact from the crisis on a macro-level construction economic indicator, namely construction demand. The methodology comprises six main stages to produce appropriate VEC models that describe the characteristics of the underlying process. Research findings suggestthat overall residential and non-residential construction demand were affected significantly by the recent crisis and seasonality. Non-residentialconstruction demand was disrupted more than residential construction demand at the crisis onset. The residential constructionindustry is more reactive and is able to recover faster following the crisis in comparison with the non-residential industry. The VEC model with intervention indicators developed in this study can be used as an experiment for an advanced econometric method. This can be used to analyse the effects of special eventsand factors not only on construction but also on other industries.

A comprehensive framework for assessing the life-cycle energy of building construction assemblies

Building environmental design typically focuses on improvements to operational efficiencies such as building thermal performance and system efficiency. Often the impacts occurring across the other stages of a building's life are not considered or are seen as insignificant in comparison. However, previous research shows that embodied impacts can be just as important. There is limited consistent and comprehensive information available for building designers to make informed decisions in this area. Often the information that is available is from disparate sources, which makes comparison of alternative solutions unreliable. It is also important to ensure that strategies to reduce environmental impacts from one life cycle stage do not come at the expense of an increase in overall life-cycle impacts. A consistent and comprehensive framework for assessing and specifying building assemblies for enhanced environmental outcomes does not currently exist. This article presents the initial findings of a project that aims to establish a database of life cycle energy requirements for a broad range of construction assemblies, based on a comprehensive assessment framework. Life cycle energy requirements have been calculated for eight residential construction assemblies integrating an innovative embodied energy assessment technique with thermal performance modelling and ranked according to their performance. © #2010 Earthscan ISSN: 0003-8628.

Addressing sustainable challenges in China

Purpose

– The purpose of this paper is to present an innovative approach to addressing increasing sustainable challenges facing China's built environment which are linked to a diverse range of factors including rapid economic and population growth. The research context includes mass urbanisation in and the Chinese construction industry's attitude towards adopting sustainable construction processes. The focus is placed on examining current on-site construction practices in China which have historically remained largely unchanged; this includes a high reliance on cheap labour accompanied by a substantial material waste. An alternative approach is to increase the uptake of off-site production in China's residential construction industry, however no previous studies have investigated the potential advantages and barriers of this alternative approach.

Design/methodology/approach

– In collaboration with an industry organisation a survey was completed by 110 construction professionals in China. The questionnaire referred to 21 individual factors relating to their perception about the current and potential future uptake of off-site production in construction processes in China.

Findings

– The results confirmed the existing level of off-site production in China's urban residential construction industry was relatively low. At present the cast-in-situ method was considered by stakeholders as the most effective approach. The findings also confirmed the benefits of off-site production are not fully understood by the housing construction industry in China. It is argued this knowledge gap reduces the Chinese construction industry's motivation levels when seeking to embrace the off-site production approach and adopt improved sustainable construction practices.

Originality/value

– This is an original study designed to address a gap in knowledge as there has been no previous research conducted into the use of off-site industrialised process in China. The results provide a valuable insight into the uptake of off-site production in the residential construction industry and will assist stakeholders and policymakers to increase the level of sustainability.

Mapping potential risk for housing damage from ground movement due to climate change

The performance of footings in residential construction is influenced by the degree of ground movement, particularly in reactive soils, which is driven by the magnitude of change in soil moisture. New patterns of climate are affecting residential foundations and causing serious and expensive damage. This paper produces a map of potential risk for housing damage from ground movement due to climate change. Using a geographic information system, it combines information on (1) soil moisture change related to climate, using TMI as the indicator, and (2) population growth. Preliminary results, having Victoria, Australia, in the last decade as the case study, suggest that effects of climate change on soil, and resulting impacts on house foundations, are not being taken into consideration in current planning strategies for urban development. Most of the urban growth priority zones in the study area are susceptible to medium and high risk for damage. Producing new and renovated buildings that are durable in the long term is essential for the economy, environment and social welfare. The map presented here can assist policies and strategies towards urban resilience in the context of climate change.