Several studies have documented benefits of prefabrication system (prefab) compared to the traditional building system (TBS). However, the documented benefits have been anecdotal or fragmented with reports of isolated case study projects. Few studies have looked at the objectively quantified benefits from statistical significance point of view and across building types in New Zealand. This study contributes to filling this knowledge gap by analyzing cost and time-savings, and productivity improvement achievable by the use of prefab in place of the TBS. Records of completion times and final contract values of 66 building projects implemented using prefab in Auckland were collected. The building types included commercial, houses, apartments, educational, and community buildings. The project details included final contract sums, completion dates, gross floor areas, and number of floors. Based on these details, the equivalent completion times and the final cost estimates for similar buildings implemented using the TBS were obtained from the Rawlinsons construction data handbook and feedback from some designers and contractors. Marginal productivity outcome for each building project was computed as the product of the cost and time-savings achieved using the prefab. Results showed that the use of prefab in place of TBS resulted in 34% and 19% average reductions in the completion times and costs, respectively. This also translated to overall 7% average improvement in the productivity outcomes in the building projects. Univariate ANOVA-based hypothesis test results showed that 'building type' had no significant effects on the cost and productivity improvement outcomes, but had significant effect on the time savings analyzed in the case study projects. The greatest productivity gain of 11% was achieved in house projects. These evidence-based

Purpose This study aims to answer the ‘what’ and ‘how’ questions about the key role players’ influence on the overall productivity outcomes in the lifecycle of residential buildings procured through the traditional route. Design/methodology/approach A mix of exploratory and descriptive research methods was used to obtain feedback from 179 role-players involved in various phases of the residential building lifecycle (RBLC) in New Zealand. Empirical data were analysed using content analysis, multi-attribute method and Friedman’s two-way analysis of variance. Findings Results showed that designers, building owners, main contractors and project managers were the greatest influencers of the productivity outcomes in the RBLC. The priority drivers of these key role-players’ influences on the RBLC productivity outcomes comprised poor brief interpretation, inclination to lowest tender, inadequate prior risk analysis and miscommunication of owner’s requirements and preferences to service providers, respectively. By taking proactive steps to redress their productivity inhibiting acts/omissions as identified in this study, the various role-players could contribute to significant improvement of productivity outcomes in the building lifecycle. Research limitations/implications It was not possible to interview all participants that made up the representative random samples from each role-player group due largely to workload related excuses. As a result, the findings and the conclusions may not be generalised beyond the study scope. However, the study achieved its purpose, as the main intent was to provide hypothetical constructs that could guide further confirmatory/experimental studies for residential buildings as well as for other building types. Practical implications A succinct and easy-to-follow model was developed as implementation pathway for operationalising the key findings of the study in the industry. The model highlights the Owner-Architect-Contractor Influence Triangle (OACIT) as the 20 per cent of the solutions that could deliver 80 per cent of the productivity improvement in the RBLC. Originality/value This study re-examines productivity issues not only from a life-cycle perspective but also from the perspectives of the majority of the key role-players. In addition, the OACIT concept offers a novel productivity improvement tool; it stresses that productivity in the traditionally procured building lifecycle could be optimised if the architect could focus greater attention on brief articulation and the issuance and review of design and specification information. Also, the owner should adopt productivity-enhancing procurement and contract strategies and emphasise more on value-addition and less on lowest tender price.

PurposeAutomation facilitates production activities within offsite construction (OSC) projects through computer-controlled and mechanised systems that can be programmed to deliver various products in a self-regulating sequence. Despite known benefits of automation to offsite production, the level of automation adoption in New Zealand is low. This study is an effort to understand the current status of automation within the New Zealand construction industry and to identify the barriers and enablers to its uptake.Design/methodology/approachThis study utilises the qualitative approach of semi-structured interviews (open-ended questions). Using a referral sampling strategy (snowballing), fifteen New Zealand industry experts were interviewed, and the data collected were analysed using qualitative content analysis.FindingsThe study found that there is a weak business case for full automation. Four main categories of barriers to the uptake of automated OSC were identified, including requirement of high capital cost, lack of education about automation and OSC and non-existence of regulations to support OSC. It was noted that financial supports to the OSC sub-sector in form of subsidies, tax waivers, and enhanced leasing model could enhance the uptake of automation. Further to this more awareness about OSC's automation and regulations suitable for OSC could enhance the confidence of business owners to invest in this area.Originality/valueOriginality of this paper stems from the fact that, not much attention has been paid to investigating the uptake of automation for OSC sub-sector of construction industry in New Zealand context.

Public private partnerships (PPPs) have gained widespread adoption as an innovative way of procuring public infrastructure projects over the last two decades. Risk identification, assessment, and allocation have received considerable attention from researchers due to the risk heavy nature of PPP projects. Adoption of PPPs has triggered a sudden increase in research interest in the area in recent years. This study attempts to provide an updated systematic review of literature related to risks in PPPs using a PRISMA flowchart. The results of the study offer some valuable insights into the future and current state of research. The study found that the focus of research on PPPs has shifted from an overall risk identification and assessment approach to individual risk analysis. Moreover, this research trend is on the rise in developing countries, and that quantitative methods for risk management in PPP research and qualitative methods in practice are preferred. In developed economies, due to negative public sentiments, transparency concerns, and arguments of value for money not being achieved, PPPs are becoming less popular. For these reasons a shift to availability-based payment mechanisms such as in Design-Build-Finance-Maintain (DBFM) from traditional revenue-based mechanisms as in Build-Operate-Transfer (BOT) has been observed. These shifts in research trends and practice offer researchers future opportunities to investigate these relatively newer approaches.

The attention on prefabricated modules and components is resurging in the New Zealand residential construction industry. This is driven by its relative benefits and technological advancements. However inspite of this attention, there has not been commensurate understanding of its manufacturing supply chain and the enhancement of their performance. Similarly, there has been little research considering the supply chain and supply chain integration in module/component manufacturing in residential construction in New Zealand. Therefore, this paper presents a comprehensive overview of the modular manufacturing process and the barriers and enablers for supply chain integration in module manufacturing. The identified barriers are discussed with their relevant enablers. Information for the study investigation was collected through twelve semi-structured face to face interviews with prefabrication experts. The information obtained was analysed using content analysis that enabled the development of a framework that illustrates barriers and enablers for supply chain integration. Ad-hoc relationships, poor planning and scheduling, transporting of volumetric modules and information sharing are a few significant barriers in the manufacturing process of modular bathroom pods and wall panels in New Zealand. The proposed framework provides a guide for the wall panel and bathroom pods manufacturing companies to improve integration across their entire manufacturing process.