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.

Sustainable construction : reliable forecasting for building construction prices

A reliable forecasting for future construction costs or prices would help to ensure the budget of a construction project can be well planned and limited resources can be allocated more appropriately in construction firms. Although many studies have been focused on the construction price modelling and forecasting, few researchers have considered the impacts of the global economic events and seasonality in price modelling and forecasting. In this study, an advanced multivariate modelling technique, namely the vector correction (VEC) model with dummy variables was employed and the impacts of the global economic event and seasonality were factored into the forecasting model for the building construction price in the Australian construction market. Research findings suggest that a long-run equilibrium relationship exists among the price, levels of supply and demand in the construction market. The reliability of forecasting models was examined by mean absolute percentage error (MAPE) and The Theil's inequality coefficient U tests. The results of MAPE and U tests suggest that the conventional VEC model and the VEC model with dummy variable are both acceptable for forecasting building construction prices, while the VEC model that considered external impacts achieves higher prediction accuracy than the conventional VEC model does.

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.

Exploring Australian housing supply volatility

This study examines the volatility series of housing supply in Australia. A Generalised Autoregressive Conditional Heteroskedasticity-in-Mean (GARCH-M) model is employed to analyse the volatility series of Australian housing supply over the study period of 1974-2010. The results show the volatility of housing starts is negatively linked to housing starts, suggesting that higher uncertainty does lower housing starts. The results also reveal that the uncertainty of housing starts is also captured by the volatilities of interest rates and construction costs. Therefore policy makers should monitor and attempt to minimise the volatility of housing supply. These steps will enhance housing construction activities and increase the availability of housing supply to potential home buyers.

Validating the impact of EVM on project life cycle

With the inevitable increase in size and complexity of construction projects, the need for proper control is increasing. Considering the fact that each project strives for excellence, numerous studies have been conducted over the years to measure performance and investigate factors that are really critical towards project success. Earned Value Management is a project performance evaluation technique which enables industry professionals to closely monitor project performance in both time and cost .The aim of this paper is to examine the result of proper Earned Value Management (EVM) implementation on different project life cycle (PLC) and validate the impact on project success.

The study investigates different success factors in construction industry with special focus on previous researchers’ work which studied the importance of cost control in project success especially in fragmented industry like construction, followed up with three different case studies to analyze the positive impact of EVM implementation on construction projects. Furthermore, for data triangulation purpose, case study analysis will be supported by interviews with specialists working in the UAE construction industry to cross check the outcomes of previous researches.
The research shows that EVM application on cost control in construction projects is not only a crucial management task which is a key to the success of the business but also its influence on project success depends on the time of implementation. It requires a number of up-to-date input data consistently throughout the construction phase. Assigning the right budgets, calculating accurate estimates and monitoring actual costs throughout different project stages are the three main drivers of an effective control through PLC staring from inception stage till completion. EVM proved to be of vital importance due to alarming escalation of construction costs which needs to be especially monitored and controlled. Senior management support and availability of professional staff to execute cost control systems are key factors towards successful implementation

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.

Testing hypotheses about the function of repeated nest abandonment as a life history strategy in a passerine bird

Nest structures are essential for successful reproduction in most bird species. Nest construction costs time and energy, and most bird species typically build one nest per breeding attempt. Some species, however, build more than one nest, and the reason for this behaviour is often unclear. In the Grey Fantail Rhipidura albiscapa, nest abandonment before egg-laying is very common. Fantails will build up to seven nests within a breeding season, and pairs abandon up to 71% of their nests before egg-laying. We describe multiple nest-building behaviour in the Grey Fantail and test four hypotheses explaining nest abandonment in this species: cryptic depredation, destruction of nests during storm events, and two anti-predatory responses (construction of decoy nests to confuse predators, and increasing concealment to 'hide' nests more effectively). We found support for only one hypothesis - that abandonment is related to nest concealment. Abandoned nests were significantly less concealed than nests that received eggs. Most abandoned nests were not completely built and none received eggs, thus ruling out cryptic predation. Nests were not more likely to be abandoned following storm events. The decoy nest hypothesis was refuted as abandoned nests were constructed at any point during the breeding season and some nests were dismantled and the material used to build the subsequent nest. Thus, Grey Fantails are flexible about nest-site locations during the nest-building phase and readily abandon nest locations if they are found to have deficient security.

An analysis of factors influencing waste minimisation and use of recycled materials for the construction of residential buildings

Residential building construction activities, whether it is new build, repair or maintenance, consumes a large amount of natural resources. This has a negative impact on the environment in the form depleting natural resources, increasing waste production and pollution. Previous research has identified the benefits of preventing or reducing material waste, mainly in terms of the limited available space for waste disposal, and escalating costs associated with landfills, waste management and disposal and their impact on a  building company's profitability. There has however been little development internationally of innovative waste management strategies aimed at reducing the resource requirement of the construction process. The authors contend that embodied energy is a useful indicator of resource value. Using data provided by a regional high-volume residential builder in the State of Victoria, Australia, this paper identifies the various types of waste that are generated from the construction of a typical standard house. It was found that in this particular case, wasted amounts of materials were less than those found previously by others for cases in capital cities (5-10 per cent), suggesting that waste minimisation strategies are successfully being implemented. Cost and embodied energy savings from using materials with recycled content are potentially more beneficial in terms of embodied energy and resource depletion than waste minimisation strategies.

Estimating demolition costs for single residential buildings

With the increasing stock of aging structures, building
demolition is becoming achallenging research field from
the perspective of management. As the converse of
construction, management of demolition puts forward some
new management themes or adds some new contents
even though the same issues are faced in construction
management. This research aims to develop a quantitative
approach to estimate the costs of a demolition project. A
cost analysis method is presented to systematically break
down the cost components involved in the demolition of
a structure. Due to the lack of robust research in theory
and systematic summary in practice to date, the economic
performances of demolition will be studied through acase
study, and the majority of parameters are derived from
actual experiences in practice. The proposed demolition cost
estimation method is applied to the actual form of building
elimination (Scenario 1), and further comparison is carried
out with two other elimination methods, which are the newly
developed deconstruction (Scenario 2) and mechanical
demolition (Scenario 3). Deconstruction is found to be the
most profitable in this particular instance, and is closely
followed by the actual form.

Case study of demolition costs of residential buildings

Building demolition is one of the most common activities in the construction industry. Several demolition techniques are commonly used, including mechanical demolition, deconstruction and hybrid demolition. Although deconstruction has been advocated for its environmentally friendly approaches, the cost comparison of a demolition project under different techniques is rarely researched. In this paper, the cost of a demolition project is broken down to input and output costs, which are further broken down to more countable sections. Through an empirical study in Victoria, Australia, project costs of mechanical demolition, hybrid demolition and deconstruction are investigated. It is found that deconstruction has the greatest profitability among the three techniques. Hybrid demolition, which is the actual technique adopted by the contractor, has a slightly lower profit, and mechanical demolition is the most expensive. Although deconstruction has the best overall economical performance, the small extra gain comes with increased complexity and risk that deters demolition contractors from its attempt. It is found in the paper that an optimized demolition project strategy exists between hybrid demolition and deconstruction with the greatest profitability among various building demolition techniques.

Modelling greenhouse gas emissions for Australian residential building construction

International pressure to reduce greenhouse gas emissions has forced many countries to look beyond 'demand side' measures. Several industry sectors are examining indirect requirements for energy and other resources that involve significant greenhouse gas emissions. The operation of buildings is responsible for approximately one quarter of greenhouse gas emissions in Australia. Moreover, he construction process consumes vast quantities of raw materials and complex goods and services each year. Each of the processes required for the provision of these products requires energy, and most of this is fossil fuel based. A national model of greenhouse gas emissions is required for residential building construction, to indicate where emissions reduction strategies should focus. A disaggregated input-output model is developed for the Australian residential building construction sector, and recommendations are made about how this model can be used in the development of policies of emissions mitigation for both the sector and individual residential buildings.

Bryan the builder-residential work only

The High Court, in the 1995 landmark case of Bryan v Maloney, held a builder of a residential house liable to a subsequent owner for economic loss suffered by way of the reduction in value of the house caused by its defective foundations. Since that decision, several cases in state courts have indicated that any extension of the principle in Bryan to commercial properties is a matter for the High Court. This year, Woolcock Street Investments Pty Ltd v CDG Pty Ltd provided the vehicle for the High Court to revisit the Bryan principle in a commercial context. Faced with the question 'can a subsequent owner of a commercial property who discovers faulty foundations sue the builder for the costs of fixing the problem before it causes any physical damage to person or property?', the resounding response from the High Court has been 'no'. Gleeson CJ, Gummow, Hayne and Heydon JJ in a joint judgment and McHugh J and Callinan J in separate judgements rejected any 'extension' of the Bryan principle to commercial premises. Much to the relief of the construction industry, the Court made it clear that it will be difficult for a subsequent owner to make out a case in negligence against the original builder unless it can show special vulnerability to the risk of injury. Kirby J, in a dissenting judgment, suggested that the extension of liability to commercial builders fits quite comfortably with general principles and lamented the 'incremental' approach to liability presently favoured by the Court. Consequent upon the retirement of Gaudron J, Kirby J appears to be a lonely light on the hill, shining a solitary beacon on matters of principle.

The revisitation of Bryan has long been anticipated. However, Woolcock does not provide the solid bricks and mortar craved by the construction industry. Close examination of the reasoning of the Court suggests that it may itself rest on faulty foundations. In his dissenting judgment, Kirby J questions some of the assumptions made by the majority and highlights the deficiencies of the 'stated case' procedure for a re-examination of this particular area of law, thus suggesting that Woolcock may not be completely sound.