Korean housing policies and housing market have come to center on apartment housings, because the country’s rapid urbanization process has created a demand for a supply of mass housing units. Consequently, the quality of large complex apartment housing has improved over time, and people can now buy apartments with confidence since they are constructed through an institutionalized supply process that involves medium-scale to large-scale companies. On the other hand, small single-family and multi-family houses, each built on an individual lot by an architect and a builder at the owner’s request, do not follow a systematic supply process, hindering the realization of uniform quality. Also, when these small houses encounter problems in their performance or require refurbishing and/or retrofitting, the owners (or the residents), often lacking in expertise, tend to have difficulty in finding solutions and are burdened with extra costs.