Post-Handover Defect Risk Profile of Residential Buildings Using Loss Distribution Approach

Abstract

Managing defect risks is a highly challenging task because various defect characteristics are complexly interconnected under the multiple dimensions of various factors. It is vital to improve the efficiency of defect risk management, and major defects and defect characteristics need to be accordingly identified by closely analyzing the defect occurrence profiles. In this respect, this study constructed a defect risk matrix based on defect type, work type, and defect location, and assessed the defect risk profile of residential buildings using a loss distribution approach (LDA). The study analyzed 16,701 defect cases in 133 residential buildings that had defect disputes between 2008 and 2017 in Korea. To summarize the analysis results, in the case of structure work, the concrete cracks and damage of public locations, which are greatly affected by external environmental factors, had a high defect frequency. Furthermore, the defect types that require rework, such as incorrect installation and missing task, had a high defect severity. When the defect risk profile was examined through defect loss, the concrete cracks on the exterior walls had relatively high defect risks because they involve water problems and surface appearance. In addition, the waterproof work for underground parking lots had a very high defect risk that requires rework. This study proposes defect risk management strategies reflecting the analyzed characteristics of the defect risk profiles, to be considered in the construction, handover, post-handover, and occupancy phases. These have been derived in detail based on three risk zones: low frequency high spatial (LFHS), low frequency low spatial (LFLS), and high frequency low spatial (HFLS).