An analysis of the causes and impact of rework in construction projects

Abstract

This study investigated the underlying causes of rework in construction projects and the impact on overall project performance so that effective containment and reduction strategies can be developed. The objectives of the study were as follows: (i) to determine the influence different project types have on the causes of rework in construction projects; (ii) to determine the impact of rework on organisational and project performance; (iii) to determine the influence various project types have on rework costs (direct and indirect) in construction projects; (iv) to determine the influence various procurement methods have on total rework costs in construction projects; (v) to design and develop rework reduction and containment strategies. The research was motivated by several international and local studies demonstrating a lack of concern for the root causes of rework and the potential impact on cost, overall project performance, and the ‘value-addedness’ to the completed project. The research approach adopted included an exploratory and main study targeting purposively selected construction professionals and stakeholders in the Cape Peninsula metropolitan area of the Western Cape Province. The exploratory case study was carried out at the initial stage of the study to gain more insight into the causes and impact of rework on overall project performance. Specifically, data was collected by means of observation of physical works, semi-structured interviews with relevant parties directly involved in site operation and the analysis of site instruction record documents. The main study obtained data from 78 construction professionals and stakeholders via questionnaire survey, a survey conducted among design consultants and contractors in the general building category ranging from grade 3 to 9 who are registered with Construction Industry Development Board (CIDB). Descriptive, inferential statistics and probability distribution functions were used to analyse the data. The findings revealed that changes initiated by the client, changes initiated by the design team due to errors and omissions, poor coordination, and finally, integration among the design team were the major contributing factors to rework. Moreover, non-compliance with specifications, setting-out errors, low labour skills, and emphasis on time and cost aggravated the occurrence of rework on site. The study revealed that while there is no significant difference between the causes of rework and various project types, rework can and often does make a significant contribution to any project’s cost overrun. The total mean cost of rework as a percentage of the original contract value for new build project and refurbishment/renovation projects was 4.89% and 6.28% respectively. However, rework costs do not differ relative to project type or procurement method. Furthermore, the study revealed that cost overruns, time overruns and design team dissatisfaction all impacted on project performance. The findings indicate that designrelated rework can be minimised by implementing the following strategies: team building, involvement of subcontractors and suppliers, and design for construction. Moreover, involvement of subcontractors during construction, and the implementation of quality control and site quality management systems could also lead to reduction in rework during the construction phase. Furthermore, the probabilistic analysis of rework occurrence was determined in the projects selected; this analysis predicts the occurrence of rework so that a quantitative risk assessment could be undertaken prior to the commencement of construction. The research concludes by recommending that design and construction firms must develop organisational measurement systems for recording rework occurrence and its associated costs. It is by determining the frequency and costs of rework that effective strategies for its containment and reduction can be identified.