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In this paper, the implementation of effective waste management practices in construction projects and sites is analyzed, using data from a survey answered by 74 Spanish construction companies based in Catalonia. Most commonly implemented practices were found to be on-site cleanliness and order, correct storage of raw materials, and prioritization of the nearest authorized waste managers. The least widespread practices were the use of a mobile crusher on site, the creation of individualized drawings for each construction site, and the dissemination of the contents of the waste management plan to all workers, to help them to meet its requirements. Waste regulations for construction and demolition, and the corresponding construction waste management facilities, were designed before the recession in the Spanish construction sector. Current waste generation rates are still below predicted levels, and the infrastructure was designed for five times more waste generation. Even so, the percentage of reused and recycled waste currently amounts to 43%. Survey respondents highlighted various instruments and measures that would make the management of construction and demolition waste more sustainable. Most of the opportunities identified by construction firms are within the scope of government and related to a combined system of bonus and penalties and the establishment of environmental awareness and training programmes for all the stakeholders. Within the scope of authorized waste managers, firms suggested improvements such as the standardization of fees, a reduction of the time until the issue of waste management certificates, a higher number of inspections, and a change in the current model of a few large construction waste management facilities. This research is useful to better understand the current status of construction and demolition waste management in construction projects and sites. Thus, the results of this research will guide policy makers and relevant stakeholders such as contractors, clients, architects and engineers to achieve the EU target of recovering 70% of construction and demolition waste in 2020. In this sense, reliable information can help governments and professional associations to set future C&D waste management regulations, training programmes and dissemination tools, inspections, etc.Peer ReviewedPostprint (author's final draft

Although inspections occur during construction or at handover, customers do not normally participate. This situation creates a gap between quality perceived by contractors and customers. An analysis of 52,552 handover defects in 2,179 flats in Spain is presented which identified their nature, the building element and trade where these defects are located. These results are compared to previous studies that analyzed defects detected during the construction stage and those that remain after handing over the building to the client. The research reveals that structural defects are resolved during construction due to existing quality standards. However, other aesthetic and functional defects remain and/or arise at handover. Some defects are not resolved until customers complain after they first occupy the dwelling. Many functional defects arise due to the lack of involvement of end users in the early project stages.

Rework adversely impacts the performance of building projects. In this study, data were analyzed from 788 construction incidents in 40 Spanish building projects to determine the influence of project and managerial characteristics on rework costs. Finally, regression analysis was used to understand the relationship between the contributing factors, and to determine a model for rework prediction.Interestingly, the rework prediction model showed that only the original contract value (OCV) and the project location in relation to the company's headquarters contribute to the regression model. The Project type, the Type of organization, the Type of contract and the original contract duration (OCD) which represents the magnitude and complexity of a project, were represented by the OCV. This model for rework prediction based on original project conditions enables strategies to be put in place prior to the start of construction, to minimize uncertainties and reduce the impact on project cost and schedule, and thus improve productivity.

Clients' lack of involvement in defining quality requirements for dwellings built by developers leads to a perception of poor quality at the time of purchase. The research presented in this paper aims to broaden previous research on defects by analyzing the defects that remain in the post-handover stage, which usually lasts 12 months after the handover period, and identifying the factors that influence the appearance of these defects, determining whether a significant difference exists in the quality of the two main residential building types built by developers: flats and detached houses. It also analyzes and discusses the areas and elements in which the defects were detected. The data were obtained from client complaint forms completed after the handover of 95 dwellings in Spain. The data were then statistically analyzed using a t-test analysis, a 2 Pearson's parametric correlation, and a chi-square test. The research reveals that clients detect more defects in flats than in detached houses. The lower quality of the materials used in flats and the tighter schedule to which flats are subject may cause these differences.