The Single Condition for a 30-Year-Old Tower Mansion to Become a Prime Asset

Q. Can tower mansions be rebuilt?

A. Legally it's possible, but in reality, it's almost impossible. The Condominium Ownership Act requires the consent of four-fifths or more of the residents. For a tower mansion with 500 units, you need agreement from over 400 people. This is virtually impossible to gather.

Q. Why is it so hard to get consent?

A. Tower mansion owners are incredibly diverse. You have actual residents, investors renting them out, heirs who are unreachable, foreigners who can't be contacted, people still paying off loans, and seniors on pensions who can't afford additional costs. When you propose to this group that they should "each put up tens of millions of yen to rebuild," there's no way they'll reach a consensus.

Q. Won't changing the law solve this?

A. Things are moving. An amendment to the Condominium Ownership Act was passed in May 2025 and will take effect in April 2026. It will allow owners whose whereabouts are unknown to be excluded from the voting pool by court decision, and for buildings with specific issues like insufficient earthquake resistance, the requirement will drop from four-fifths to three-quarters. However, for normal buildings, it remains at four-fifths.

This lowers the hurdle slightly, but the core issue remains. You can't exclude "dissenters who can be contacted but can't afford to pay." No matter how hard the law tries, it cannot change the contents of people's wallets.

Q. Does it really cost that much?

A. Yes. It often costs between 30 million to 50 million yen per unit. Because tower mansions have so many units, the total cost for demolition and construction is astronomical. Since this is split among the owners, the burden per unit is heavy. You can't exactly ask a grandfather living on a pension for another 30 million yen.

Q. Haven't old apartments been rebuilt in the past?

A. They have. But almost all successful cases were properties with "excess floor area ratio." For example, when rebuilding a 50-unit building, they would turn it into a 100-unit building and use the proceeds from selling the extra 50 units to cover the rebuilding costs. This trick allowed residents to rebuild with almost zero out-of-pocket expense. Almost all old housing complex rebuilds follow this pattern.

Q. Why can't tower mansions do that?

A. They can't. Tower mansions are built to the maximum floor area ratio from the start, so this trick doesn't work. There is simply no room to increase the number of units. Old complexes succeeded because they had a "magic trick," but tower mansions don't. Therefore, owners have no choice but to pay out of pocket.

Q. Can't they just be demolished?

A. That's also difficult. There is almost no track record in Japan of demolishing a tower mansion over 50 stories. While methods like Kajima's "top-down crushing" exist, the cost is 30% to 50% of the cost of a new building. For a normal apartment, demolition is 5% to 10% of new construction, so this is a burden of a completely different magnitude.

Q. So what happens? Will they become ruins?

A. At this rate, that's highly likely. A negative spiral begins: more people can't pay management fees → repair funds run dry → large-scale repairs can't be done → the value of the whole building drops → wealthy people flee → the burden on those remaining increases further. Signs of this are already appearing in early properties in Musashi-Kosugi and the bay area.

Q. Is there no hope?

A. Actually, one hope is emerging. If the concept of "Economic Residual Useful Life Evaluation" spreads, the situation might change completely.

Q. What is that?

A. Under current banking rules, reinforced concrete (RC) apartments lose all value in 47 years. So if you try to borrow against a 30-year-old tower mansion, the re-evaluation only gives it 17 years of remaining value. As a result, it becomes a property that cannot be refinanced.

Q. But actual RC buildings don't collapse in 47 years, right?

A. Exactly. Well-maintained RC structures are said to last over 100 years. Therefore, the idea of "evaluating economic residual life based on reality" is becoming common in the professional real estate market (like REITs). If this trickles down to the individual mortgage market, a 30-year-old tower mansion could be evaluated as having "70 years left," making 35-year loans possible.

Q. What would that change?

A. Everything. A 30-year-old tower mansion stops being a "dilapidated building" and becomes an "asset where you can buy a location cheaply." Liquidity returns because buyers and refinancers can get loans. Money flows into the management association, allowing for large-scale repairs. If properly maintained, they really can last 100 years. Instead of rebuilding, a path opens up to continue using them through renovation.

Q. So it's like "buying a new building cheaply"?

A. Yes, it's close to that. For a tower mansion in a prime location, the land alone is worth tens of millions of yen, and you get a "structure that can last another 70 years" as a bonus. In an era where new tower mansions cost 200 million yen, buying a 30-year-old property for 50 million yen in the same location can be a rational choice.

Q. But not all tower mansions will turn out like that, right?

A. No. From here, they will polarize. Tower mansions where the management association functions well, the repair history is clean, and the location is prime will survive as "semi-new." Conversely, tower mansions with collapsed management, rampant repair fee arrears, and suburban locations will not get bank loans even if economic residual life evaluation becomes common. They are destined for the slum route.

Q. So, how can you tell them apart?

A. Three things:

① Does the management association function properly?

② Are the repair funds sufficient?

③ Is the location good?

Tower mansions that "have all three" will likely last 100 years. Conversely, if even one is missing, you should consider it a candidate for becoming a ruin.

We are entering an era where a tower mansion's success is determined not by its "price at the moment of purchase," but by the "quality of its management."