Continuous improvement and experience feedback in off-site construction : timber-framed module prefabrication

Abstract: Continuous improvement implies an incremental, ongoing effort to improve products, services or processes. Some construction companies have chosen to face competition by adopting an off-site construction strategy, one form of which is timber-framed module prefabrication. These housebuilders strive to transform their activities from conventional, loosely controlled construction into tightly controlled, continuously improved production processes.The rationale for developing and implementing methods for continuous improvement is well documented. Regardless of the choice of production strategy common denominators are needs to recognise problems and a continuous quality improvement program that incorporates learning from mistakes and success. There is greater scope for such experience feedback in off-site module manufacturing than in on-site construction, because there are higher levels of repetition and process control. The purpose of adopting a continuous improvement strategy is to create knowledge that results in improvements aligned with company vision and goals. This thesis presents and discusses a series of studies intended to elucidate the role and status of continuous improvement in Swedish off-site construction. Quantitative and qualitative data have been gathered in six studies of timber-framed module prefabrication companies: three multiple case studies, two questionnaire-based surveys, and one archival analysis. The six studies have investigated building inspection defects, current practice of experience feedback, application of stepwise problemsolving, and Lean management in an off-site construction context. The results show that application of a continuous improvement strategy through stepwise problem solving enables pull for experience feedback in the studied companies. Furthermore, stepwise problem solving can reduce defects, enhance learning and target accuracy when solving problems in module prefabrication. The investigated problems acted as vehicles for experience feedback for both internal and external customers, in a feedback generating loop. Communication was improved as it was demanded by the problem-solving activity. Further work is needed to understand how continuous improvements and the stepwise problem solving methodology could be fully implemented and integrated in working processes in the off-site construction context, in terms of supporting leadership, ensuring availability of resources, building trust among employees, providing challenging work and thus attaining sustainable quality advantages in contrast to short-term benefits. In addition, a sufficient level of standardisation must be applied in off-site construction to gain the benefits of systematic problem solving.