Concerns in 1st Generation New Towns: 'Leakage and Insulation'... Is the Culprit the Prefabricated Construction Method? [Real Estate AtoZ]

PC Construction Method Causing Issues Like Leakage and Insulation
Pilot Sites in Bundang: Woosung, Hanyang, and Ilsan Baengma 3 Complex
"Prioritize Reconstruction of Complexes Using PC Construction Method"

The Ministry of Land, Infrastructure and Transport announced the 'Plan for Selecting Leading Districts in 1st Generation New Towns' involving around 26,000 households on the 22nd of last month, drawing attention to the reconstruction of 1st generation new towns. Since the 1st generation new towns were developed in the 1990s, issues such as leaks and insulation problems due to aging have consistently raised the need for reconstruction. Particularly, such concerns have been raised in complexes where the PC method (Precast-Concrete), considered less safe, was applied. Real Estate AtoZ explored what the PC method entails.

Apartment complex in Bundang-gu, Seongnam-si, Gyeonggi-do.
Photo by Yonhap News

PC Method: Advantage of Shortened Construction Period... Applied in 1st Generation New Towns but Defects Like Leaks and Insulation Problems Occur

The PC method is a prefabricated construction technique where concrete components such as walls and floors are manufactured in a factory in transportable shapes and sizes and then assembled on-site. Installing pre-made components reduces the construction period by 30-50% compared to reinforced concrete apartments where concrete is poured on-site. Due to the nature of prefabricated apartments, remodeling is difficult, and only reconstruction is possible.

Introduced around 1988, this technology was mainly applied in the development of 1st generation new towns. According to 'Tomorrow's House, Modular: Transition to Manufacturing' released by IBK Investment & Securities in February, the average number of apartments completed between 1981 and 1990 was 116,000 units, but with the development of 1st generation new towns, the average supply sharply increased to 366,000 units. To handle such a rapid volume, the PC method was chosen for some complexes within the 1st generation new towns. Representative examples include Woosung and Hanyang in the Bundang pilot complex in Seongnam, Gyeonggi Province, and Baekma 3 Complex in Ilsan, Goyang City.

Jojung-hyun, an analyst at IBK Investment & Securities, said, "During the development of 1st generation new towns, construction companies likely felt pressure to meet construction deadlines due to the rapid increase in apartment supply. In this process, some 1st generation new town complexes were hastily built using the PC method, and the proliferation of manufacturers led to issues such as leaks and insulation problems."

While the PC method has the advantage of reducing construction time and labor costs, it has the drawback that as the building ages, leaks and insulation problems can occur at the joints. In on-site poured concrete, columns and floors are connected as one, preventing joint defects. However, since the PC method is prefabricated, gaps can develop over time at the joints where concrete components meet. Especially at the time of developing 1st generation new towns, this technology was in its early stages domestically, making it difficult to address joint issues. Consequently, on-site poured concrete became the mainstream method for apartment construction in Korea.

Despite Quality Issues in PC Method Construction, It Does Not Affect Selection of Leading Districts

Due to construction quality issues related to the PC method, some local governments have shortened the reconstruction eligibility period to 20 years for complexes built with this method. Yongin City in Gyeonggi Province classifies buildings other than reinforced concrete as aged or poor-quality buildings under the 'Yongin City Urban and Residential Environment Maintenance Ordinance.' In such cases, the reconstruction eligibility period is applied as 20 years instead of 30 years. The 'Road and Residential Environment Maintenance Act' stipulates that reconstruction projects target aged or poor-quality buildings. The reconstruction eligibility period is set by city or provincial ordinances within a range of 20 to 30 years after completion.

However, the Ministry of Land, Infrastructure and Transport stated that whether the PC method was applied is not considered a criterion for selecting leading districts for reconstruction in 1st generation new towns. Choi Byung-gil, head of the Urban Maintenance Planning Division at the Ministry, said, "Whether the structure is PC or not is irrelevant to the selection of leading districts. The consent rate showing how much residents want reconstruction is more important." He added, "There were opinions to include structural aspects like PC structures in the selection criteria," but "if we start looking at structures, it is essentially the same as conducting a safety inspection, which does not align with the purpose of selecting leading districts based on residents' inconvenience and reconstruction wishes."

A view of a reconstruction construction complex in Seoul city.
[Photo by Yonhap News]

Lee Eun-hyung, a research fellow at the Korea Institute of Construction Policy, said, "1st generation new towns have construction quality issues such as joints due to the introduction of the PC method, and even if these are supplemented, the apartments are already old. If such old apartments are to be reconstructed, complexes built with the PC method should be prioritized over those constructed with on-site poured concrete."