For decades construction labour productivity has been stagnated or declining. Changing this issue requires new knowledge on the labour-intensive construction production system. The work sampling method was applied to collect data from 3 renovation construction production systems. It quantifies observations of on-site work and enables deep analyses of how time is used. The analysis revealed that the renovation projects had a baseline of value-adding-work (VAW) time on 29.5%. It further identified 5 system behaviours outlining how VAW and Non-Value-Adding work (NVAW) time behaves. The new knowledge of how both VAW and NVAW time behaves advances knowledge on how time is wasted in construction projects and opens new branches of future research. The findings are furthermore of potential use to industry professionals who work with process improvement in renovation projects because they provide, among others, answers to how targets can be defined for both VAW and NVAW.

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Labor productivity in construction has fallen behind other industries in most of the world and has declined continuously for decades in the US. To change this, the construction industry needs to know where to focus. This research aims to show how important craftsmen efficiency is for national construction labor productivity (CLP) development. Statistical analysis was used to compare craftsmen efficiency and CLP data from North America (NA) in the period 1972-2010. Craftsmen efficiency data were extracted from published work that measured direct work (DW) through work sampling, and CLP data were extracted from national databases. A statistically significant relationship between DW and CLP was established. This revealed that adding 36 seconds of DW to every work hour could yield a yearly return of 5.4 billion USD to the NA gross domestic product (GDP). Results show that more focus on activity and project level efficiency is crucial for changing the trends of national CLP. Industry leaders and policy makers now have a solid foundation for taking corrective actions for an industry plagued by low productivity.

The elimination of waste is a core focus of lean construction. Reducing waste will increase work efficiency. For several years it has been debated how flow and the efficiency of processes can be measured. Kalsaas, Koskela, and others conclude that in order to operationalize workflow measures, it must be disconnected from productivity and throughput measures and instead focus on work efficiency. However, an extensive and valid baseline of work time efficiency is missing in the community. The establishment of such becomes the objective of this research.The method is an extensive litterateur review that identified 474 case studies of time waste measures from the 1970s until today. This sample is analyzed in different ways, among others showing that the average direct work time is 43.6%.The results show that the sample contains considerable uncertainty, which is mainly due to an inconsistent understanding of direct work, indirect work, and waste work in the many different studies. Besides, the results show no statistically significant difference between the performance of varying trades or between countries.The construction industry can use this research as a baseline for the current direct work level and apply this as a benchmark in a continuous improvement process.

Refurbishment projects have shown declining productivity in the last decades. At the same time, refurbishment activity is increasing rapidly worldwide to achieve a more sustainable built environment. Thus, understanding reasons for the low productivity is a key aspect to reach environmental as well as economical sustainability. The aim of this research has been to identify Making-Do in refurbishment projects and the reasons behind it. A case study research approach has been used to collect data by actively participating in weekly Last Planner System meetings, observing work in progress on-site on three projects and conducting work sampling studies on six trades. The research showed that Making-Do is highly likely to be both the prevailing and lead waste form in all of the three cases, and that insufficient management of production was the main cause. This was found by firstly identifying an overlap between known impacts of Making-Do from literature and the most occurring negative impacts observed in the cases. Secondly, finding that talking generally contained the biggest potential for being reduced and that this potential had an apparent correlation with Making-Do. This research is an important step towards understanding Making-Do in refurbishment projects and how to detect and reduce lead waste in refurbishment, and to improve construction productivity.

The construction industry has experienced stagnation and perhaps even a decline in construction labor productivity for decades. This is problematic as labour costs in construction constitute up to 60% of the total project costs.This research aimed to investigate further how much complimentary lean construction tools could impact Construction Labor Efficiency (CLE). CLE is a key element in the denominator when calculating Construction Labor Productivity (CLP) because CLP focuses on maximizing value-adding-work time (numerator) and minimizing nonvalueadding-work time (denominator).A case study research approach with four renovation projects was used to collect Lean Implementation Degree (LID) and CLE data. The research findings showed a strong positive correlation between LID and CLE in the four renovation projects.The findings have implications for both academia and industry professionals. Academia now has initial results on which future research can be built. Industry professionals now have a better understanding of how lean improves efficiency and hereby better arguments for why lean construction methods must be implemented in future renovation projects.The research was limited by a small sample size of only four renovation projects. Thus, further research is needed to validate the effects in renovation projects and other types of construction projects as well.

For years, the construction industry has looked for ways to avoid time-overruns in construction. Despite previous research mapping the factors affecting time performance, site-managers have difficulties in reducing the time-overrun. In order to create a clearer guidance on how to control time-performance, this study investigates the resource related factors because they are within the site-manager's control. Three Case studies were followed and a survey including 36 participants where conducted. Both investigated and ranked the likelihood of delay due to the seven different resource factors. The ranking of the resource factors was identified as: 1) Construction design, 2) Connecting works, 3) External conditions, 4) Work force, 5) Components and materials, 6) Space, 7) Equipment and machinery. The site-manager's focus should be avoiding the factors that most often is found to cause time-overrun, which are construction design and connecting work that constitute about 60% of the time-overruns. The comparison of the studies revealed that construction professionals were unable to distinguish between the less and the low frequent factors causing time-overrun. Future survey studies should take into consideration that construction professionals' preserved reality does not always correspond to the observed reality.Indicators include low variation between factors and limited use of the scale.

The European Green Deal's Renovation Wave aims to renovate 35 million energy-inefficient buildings to reduce carbon dioxide (CO2) emissions by at least 55% by 2030. Historically, efforts to reduce CO2 emissions focused on Operational Energy (OE) of the finished buildings. However, in recent years the Embodied Energy (EE) of the building’s construction process has gained attention because of its essential role in construction renovations projects. In this context, construction efficiency, and more precisely, workers’ efficiency, is a vital catalyst to achieve the European Union (EU) targets. To identify the impact of Construction Labour Productivity (CLP) on the renovation wave an exploratory case study was adopted as a research strategy. Data from four domestic housing renovation projects were gathered. Three specific research goals are outlined. The first is to demonstrate the effect of the adoption of Lean tools and methods to increase CLP. The second is to quantify the correlation between improved productivity and the EE emissions saved during the construction phase. The third goal is to estimate the effect the higher productivity has on OE emissions. The results show that the adoption of several Lean tools and methods has a potential to improve CLP to 45%.  This rate of improvement for the 35 million housing units to be renovated could save 6.9 million tonnes CO2e from EE and 386 million tonnes CO2e from OE. This novelty link between process improvements and reduced energy consumption and emissions can support politicians and infrastructural developers in decision-making for a more sustainable construction industry.