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Why age matters for Akiya and Old Homes in Japan
In recent years, low-priced detached houses in Japan have attracted growing interest from overseas buyers, and the term “Akiya” (vacant house) has become widely recognized.
These affordable homes may seem like attractive opportunities—but if purchased without proper understanding, they can come with unexpected problems later on.
This article focuses specifically on homes with significant age, outlining key points and risks that are especially relevant when evaluating older detached houses in Japan.
Rather than covering infrastructure, utilities, or location factors, the emphasis here is on how age, historical construction practices, and Japan’s unique environmental conditions impact a building’s safety and longevity.
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Divided into categories, this Q&A guides you from the first property search through to becoming an owner.
Building Age and Japan's Unique Environment
When choosing a home in Japan, it’s important not to rely on housing standards or assumptions from countries like the US or Europe.
Environmental conditions in Japan are fundamentally different, and these differences significantly affect how buildings age, how repairs and reinforcements are prioritized, and how maintenance needs to be approached.
Japan is a country with frequent earthquakes, high humidity, and regular typhoons.
As a result, construction standards and building lifespans in dry, quake-free regions simply don’t apply here.
In fact, construction methods and building techniques imported from overseas have often been revised or replaced through legal reforms and technical improvements after natural disasters—leading to Japan’s own evolving standards.
Japanese wooden houses are generally said to have a lifespan of 60 to 70 years.
In recent years, some experts suggest that with proper maintenance, these homes can last up to 100 years.
However, due to the underdeveloped nature of Japan’s secondhand housing market, there is no clear or commonly accepted standard for evaluating the quality of older homes based solely on their age.
No matter when a house was built, its actual durability and safety depend largely on construction quality and how well it has been maintained.
That said, each era presents different structural and legal risks.
In Japan’s high-humidity, disaster-prone environment, age-related deterioration can be significant, and older homes were built under different regulations that may no longer meet today’s standards.
Understanding the relationship between a home's age and the building codes in effect at the time is essential to avoiding unexpected problems.
Earthquake Resistance Is About Protecting Lives, Not Buildings
One of the most important factors in choosing a home in Japan is earthquake resistance.
While many overseas buyers became aware of the danger of tsunamis after the 2011 Great East Japan Earthquake, it's important to understand that earthquakes themselves—unlike tsunamis—can strike anywhere in Japan, at any time.
Japan has experienced numerous major earthquakes throughout its history.
From those experiences, the country has developed seismic building standards (taishin kijun) designed to minimize the risk of collapse and protect human life.
These standards have been revised and strengthened repeatedly over the years, especially in response to large-scale disasters.
Major Revisions to Japan’s Earthquake Resistance Standards
Japan’s seismic standards have undergone several major revisions over time.
Here are three key milestones you should be aware of:
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1971 Revision: Strengthening of joint reinforcement between columns and beams became mandatory.
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1981 Revision (New Seismic Standard): Homes must be designed not to collapse even under strong seismic activity—equivalent to intensity levels 6+ to 7 on the Japanese scale.
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2000 Revision: Additional requirements introduced for foundation surveys, placement of structural walls, and the use of metal connectors—aimed at improving structural balance overall.
Among these, the 1981 revision is particularly significant.
Homes built before June 1981 fall under the category of “old seismic standard”, while those built afterward are classified as “new seismic standard” .
This date is widely recognized as a dividing line when evaluating earthquake safety in older properties.
Caution When Considering Homes Built to the Old Seismic Standard
It’s important to understand that Japan’s seismic standards are based on the condition of a building at the time of construction.
As a home ages and structural elements deteriorate, it can no longer be expected to meet its original seismic performance—especially if no retrofitting has been done.
For homes built under the pre-1981 standard, it is highly recommended to assess their current earthquake resistance through a professional inspection.
If deficiencies are found, seismic retrofitting may be necessary.
However, this process can involve significant cost and logistical complexity, and is not always a practical solution depending on the home’s overall condition and the buyer’s plans.
Construction Methods and Materials Vary by Era
The construction techniques and materials used in a home can vary significantly depending on when it was built.
Homes built prior to the 1970s often differ greatly from modern standards—not only in terms of safety but also energy efficiency and comfort.
Common characteristics of homes from this era include:
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Handcrafted construction by carpenters, before pre-cut processing became standard
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Solid wood used for pillars and flooring
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No insulation, with hollow wall cavities
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Foundations made from unreinforced concrete strips (musen nuno-kiso)
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Little to no structural calculations, and minimal attention to wall placement for stability
These homes often have aesthetic appeal—such as natural materials, open floor plans, or traditional design details—but structurally, they may fall far short of modern safety and comfort expectations.
Since formal standards were not as clear or strict as they are today, construction quality from this period can vary widely.
In many older homes, deterioration of structural elements, materials, and foundations may not be visible but still pose serious risks—especially when the home is approaching 60–70 years of age, the typical lifespan of a wooden house in Japan.
Be Cautious About Asbestos in Older Homes
In older properties, asbestos may have been used in insulation materials, sprayed coatings, or exterior wall panels.
Although asbestos was fully banned in Japan in 2006, homes built before that year may still contain it.
If asbestos is present, special removal procedures are required, and the cost of demolition or renovation can increase significantly.
However, many older homes have never undergone asbestos inspection.
If you're considering major renovations or demolition, a professional asbestos assessment is strongly recommended before proceeding.
Review of Repair History and Vacancy Period
When considering the purchase of an older or vacant home, the property's repair history and length of vacancy are crucial pieces of information.
While buyers often focus on the condition of kitchens, bathrooms, and interior finishes, what truly affects the longevity of a home are repairs and reinforcements to the structure, foundation, and roof.
Key upgrades to look for include flooring replacements, exterior siding renewal, and roof re-roofing—all of which have a major impact on structural soundness.
Once a home has been standing for more than 30 years, minor repairs and equipment updates may no longer be enough.
More substantial reinforcement or renovation work is often necessary, and whether this has already been done will significantly affect future maintenance costs.
Vacancy history also plays an important role in assessing the home's condition.
Homes left unoccupied for long periods are prone to poor ventilation, unnoticed leaks, corrosion, rodent or insect intrusion, and other forms of hidden damage—even if the property appears clean on the surface.
In colder regions, damage from frozen pipes or snow buildup on the roof can also be a concern.
However, many older homes have no clear repair record.
In some cases, the seller hasn’t lived in the property for years or inherited it through succession and may not be aware of its condition.
For these reasons, a professional inspection becomes essential.
The Importance of a Professional Home Inspection
Older homes often come with hidden risks and structural issues.
However, most real estate agents in Japan are not construction experts, and the information they provide may be limited.
That’s why, whenever possible, it’s highly recommended to conduct a professional inspection (building condition survey) before purchasing an older property.
Real Example: A Hole in the Foundation
In one case, a buyer requested an inspection of a house built in 1978.
The inspection revealed a large, unusual hole in the foundation.
It turned out that the house had an unreinforced strip foundation (musen nuno-kiso) with no original crawlspace access, and a contractor had later broken through the foundation to apply termite treatment—leaving behind structural damage.
This kind of issue is nearly impossible to detect through visual checks alone.
It’s a good example of how professional inspections can uncover problems that would otherwise remain hidden.
Barriers to Home Inspections in Japan
Unlike in many Western countries, pre-purchase home inspections are not yet standard practice in Japan’s secondhand housing market.
In fact, some sellers and many listing agents may view inspections as a risk to the transaction, fearing that problems uncovered could lead to renegotiation or cancellation.
As a result, buyers are sometimes refused an inspection, or face difficulty arranging one before signing a contract.
That’s why it’s important to express your intention to conduct an inspection early in the negotiation process.
Check whether the seller is open to it, and involve your agent in the discussion as soon as possible.
Making the Inspection a Condition of the Contract
Depending on the situation, it’s possible to include a special clause in the contract that makes the sale conditional on the results of an inspection.
For example:
“This agreement is contingent upon the completion of a building condition survey (home inspection).
If the inspection reveals major defects or facts that materially differ from the seller’s prior explanation, the buyer reserves the right to cancel the contract.”
By including a clause like this, buyers can reduce their risk and make sure that any unknown issues discovered during the inspection are legally recognized in advance.
Talk to your agent early to see if such terms can be negotiated before signing the contract.
Keep in mind: if a property is cheap, there’s a reason.
Make your decision based on careful research and thoughtful consideration.