The housing policy of the Seoul Metropolitan Government focused on expanding the supply of new homes during the period of high growth. As a result, it preferred demolition and redevelopment to repairs and improvements for the purpose of increasing the housing stock in Seoul. However, the potential economic growth is slowing down today, and it is expected that the number of households is going to decrease after the mid-2030s, as is the population. Around 3.9% of total housing stock in Seoul consists of ageing stock whose administrative durability periods exceed their economic durability periods. If there is no supply of new homes in the future, this proportion will likely increase up to 5.7% in five years and up to 11.4% in 10 years. In the era of low growth, it is important that housing stock be reserved and managed properly, not only by providing newly-built houses, but also by promoting the quality of used houses.

In order to increase the durability of existing houses and promote voluntary improvements and renovations by homeowners, the housing stock management policy of Seoul city needs to follow three principles. First, the administrative durability periods of buildings should be gradually set to be equal to the economic durability periods. Second, the goal of housing stock management should be set up as the achievement of long-lasting buildings with a focus on health, safety, and habitability (incl. barrier-free design and energy efficiency). Third, the response and management for ageing stock should maintain a balance between point- and area-based approaches.

This research provides three new directions for achieving the goal of housing stock management. First, housing improvement and renovation assistance programs need to be improved. It is necessary to modify the requirements for housing improvement assistance and to make an upward adjustment of the administrative durability period. With this policy goal taken into account, programs should establish their targets properly, as well as the types and contents of improvement work. In addition, incentives for housing improvement need to be complimented by the introduction of tax-cuts and an increased limit of the amount of improvement work assistance. In the long run, it is desirable that Seoul city operates the investigation and assessment system used to evaluate the qualities and performances of houses.

Second, a systematic organisation and operation system is needed to establish a better housing improvement system. It is recommended that two divisions in the Seoul Metropolitan Government, that is, the Housing Policy Division and the Residential Environment Improvement Division, cooperate with each other to establish housing improvement governance of local communities. A quality certification system for housing improvement companies would help build public confidence in their works. In the long term, it would be extremely useful to set up a housing inventory management system that manages a database containing all relevant data and information such as construction, improvement, maintenance, etc.

Third, transactions of used houses need to be promoted by modifying relevant institutions. It is necessary to upgrade the current certification standard, such as by establishing long-lasting building conditions, and it ought to be ensured that a new standard can be met through housing improvements and renovations. The public assistance that can be provided in housing transactions should be reinforced to create a situation where improvements or renovations can be carried out when transactions involving used houses occur.