Due diligence
Japan's 1981 Earthquake Standard: How to Read a Building's Age
What changed in June 1981, why the permit date matters more than the completion year, and what to check before buying an older Tokyo condominium.
Many resale condominiums in Tokyo are more than 40 years old. In a country with frequent earthquakes, the standard a building was designed to affects not only safety but also financing, tax relief and resale. This guide explains the rule of thumb from the building age and what to check before you sign.
Key takeaways
- The new earthquake standard applies to buildings whose permit was granted on or after 1 June 1981
- The permit date decides it, not the completion year; buildings completed 1981–83 need checking
- An older building can still be assessed and reinforced
- Older standards can affect loan terms and tax relief
What changed in 1981
The Building Standards Act was revised in June 1981. Buildings designed to the new standard should suffer little damage in moderate earthquakes (around seismic intensity upper 5) and should not collapse in rare, severe ones (upper 6 to 7).
The earlier standard mainly aimed to keep buildings standing in quakes of around intensity 5. Surveys after major earthquakes found heavy damage concentrated in buildings designed to the old standard, which is why the rules were tightened.
Reading the building age
Whether the new standard applies depends on the date the building permit (建築確認) was granted, not on when the building was finished. Condominiums often take one to two years to build, so buildings completed around 1981–1983 must be checked against documents.
Our listing pages show a hint from the completion year: 1984 and later, new standard; 1981–1983, check the permit date; earlier, likely the old standard. The final answer comes from the permit documents.
- The permit date is on the confirmation certificate or the building plan summary held by the ward office
- For older buildings, the formal disclosure before the contract states whether a seismic assessment was carried out and its result
- Drawings and repair records kept by the owners association help too
If you consider an older building
Some old-standard buildings have passed a seismic assessment or been reinforced. Ask whether the owners association has assessed the building or plans to, and whether the repair reserve can cover the work.
Old-standard properties are often cheaper and can show higher yields. Weigh that against future reinforcement costs, possible redevelopment discussions and how easily you could sell later.
Loans and tax
Some lenders shorten loan terms or lower the collateral value for old-standard buildings. If you will borrow, check the lender's conditions early.
For tax relief such as the mortgage tax deduction, homes whose registered construction date is 1 January 1982 or later are treated as meeting the new standard. Earlier buildings need a certificate showing they comply.
Checklist before you sign
Whatever the building age, these points are worth confirming.
- The permit date and which standard applies
- Any seismic assessment or reinforcement, and the results
- The long-term repair plan and when major repairs are due
- The repair reserve balance and planned increases
- Your lender's conditions, if you will borrow
FAQ
Should I avoid old-standard buildings?
Not automatically. Compare the assessment and reinforcement status, management, price and repair plans, and check how loans and tax relief are affected.
Is a condominium completed in 1982 built to the new standard?
The completion year alone cannot tell you. If the permit was granted before 1 June 1981, it is old-standard. Check the permit date in the documents.
Does the new standard mean no earthquake damage?
It aims to prevent collapse in a major earthquake; it does not guarantee no damage. Also look at ground conditions, maintenance and local hazard maps.
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