Lean construction relies on the distinction between value adding and non-value adding activities, and reducing workflow variability is one technique for reducing non-value adding activities. Planning controls such as the ‘last planner’ can go a long way in improving workflow reliability, but are limited in their capability to the extent they can expect the unexpected. The occurrence of specific defects in construction is, by the very fact of its happening, an unexpected event because whatever could be anticipated would be avoided. On the other hand, defects in construction have the compound effect of increasing workflow variability,as well as non-value adding activities in the form of rework.This paper explores two aspects of this problem, first of all a number of different tools were developed and trialed to explore their potential for improving defect avoidance, secondly the paper presents a generic analysis of the increase in rectification cost with time from an error being made. The paper outlines the implementation of trade start-up checklists; a management tool that was found to be particularly effective at improving quality outcomes on site.
Construction defects, Work flow variability, Time to rework, Defect incident record, Checklists