Tokyo steps up seismic outreach to thousands of older condo buildings

The Tokyo Metropolitan Government has begun individually approaching approximately 3,700 older condominium buildings that have not undergone seismic diagnosis, in a five-year effort to encourage assessment and, where necessary, upgrading.

The visits began September 1, and target condominiums built under Japan's old seismic standards where Tokyo's records indicate that a seismic diagnosis has not been completed.

Screengrab from the Tokyo Metropolitan Government News site, linked at the bottom of the article.

Tokyo is not saying that 3,700 buildings have inadequate seismic resistance. These are buildings whose seismic performance has not been established through the relevant assessment process. An unassessed building has not necessarily failed an assessment.

Tokyo is working with ward and municipal governments to visit the buildings. Properties receive advance notice by mail.

During a visit, officials or contractors conduct a simple exterior visual inspection, provide information about seismic diagnosis and upgrade, and explain available support programs. The exterior inspection is not a formal seismic diagnosis.

Why the 1981 date matters

Japan strengthened its national seismic requirements from June 1, 1981. The earlier rules are commonly called the "old seismic standard," while requirements introduced from that date are known as the "new seismic standard."

Construction year alone does not always determine which standard applies. Tokyo's support program defines eligible old-standard buildings by building confirmation obtained on or before May 31, 1981.

A condominium completed after June 1981 can therefore still have been approved under the earlier rules.

Old-standard status does not itself mean a building is unsafe. A seismic diagnosis assesses a building's seismic resistance.

A retrofit is physical work to improve it. Rebuilding means demolishing and replacing the building.

What the program means for owners

Tokyo already offers seismic support through wards and municipalities, including specialist advice, diagnosis and, depending on the area, assistance with retrofit-related work.

The new element is proactive outreach. Tokyo is identifying unassessed buildings and approaching management associations directly rather than waiting for them to act.

For owners, the first step is establishing whether a formal diagnosis has been completed and what support is available.

If a diagnosis finds inadequate seismic resistance, the management association must then consider the next steps, which may include retrofit planning or longer-term rebuilding discussions.

Because condominiums are collectively owned, major work can require agreement among multiple unit owners and decisions about funding.

Clear records of building confirmation, diagnosis and any completed retrofit can also reduce uncertainty when units are later sold.

Tokyo's 3,700-building program is therefore not a finding that thousands of condominiums are unsafe. It is an effort to establish the seismic status of older buildings that remain unassessed and help owners decide what, if anything, should happen next.

Further Reading:

Individual Visits to Condominiums Without Seismic Diagnosis (Japanese only)

Condominium Seismic-Resistance Promotion Program: Individual Visits and Specialist Dispatch (Japanese only)

Condominium Seismic-Resistance Promotion Program: Subsidies and Support (Japanese only)