With a property lifespan of just 30 years, construction is constant and so is the housing stock. More estates may be one solution

Housing units on the production line at Japanese motor manufacturer Toyota's housing works in Kasugai. Photograph: Junko Kimura/Getty

It's time to move to a new city. You look at houses you might want to buy and finally settle on one that's in the right location and appeals to you. But in Japan, that appeal hardly matters: the average home only lasts for 30 years.

That's because, as the economists Richard Koo and Masaya Sasakishow in a report, 15 years after being built the average house is worth nothing. "It's a direct contrast to, for example, western Europe, where many of the most desirable buildings are 200 years old," notes Alastair Townsend, a British architect living and working in Japan. "It's not environmentally sustainable but also not financially sustainable. People work very hard to pay off a mortgage that's ultimately worth zero."

The disposable-home culture has led to a perverse market, where construction is in almost-perpetual boom without the number of homes increasing much at all. It has also produced a huge number of architects, who are kept busy by buyers wanting a new house that reflects their lifestyle. According to the International Union of Architects, Japan has almost 2.5 architects per 1,000 residents, whereas Britain only has half an architect per 1,000 residents. The US has only 0.33 architects per 1,000 residents and Canada has 0.22%. Japan, in other words, has 11 times as many architects per capita as Canada.

The origins of this unusual approach to sturdy structures are the result of a long history featuring earthquakes and fires. The second world war exacerbated the situation.

Jiro Yoshida, an assistant professor of business at Pennsylvania State University, specialises in the Japanese housing market. "Most structures in, for example, Tokyo were destroyed, so everything had to be rebuilt from scratch," he says. "The new buildings weren't very good, so after a while many had to be knocked down."

But today's buildings are demolished even though they could last. That, says Yoshida, has a cultural explanation: "The government updates the building code every 10 years due to the earthquake risk. Rather than spending money on expensive retrofitting, people just build new homes."

That's good news for the Japanese economy, but less good for homeowners themselves. They seem to accept the situation, however, often even neglecting to properly maintain a home they know is on track for demolition. But the real victim is the environment: replacing the entire housing stock within a generation means a whole lot of construction waste.

Granted, a law passed in 2000 requires that most forms of demolition waste be recycled, and more than 80% of it is. But recycling consumes large amounts of energy and yields less valuable materials than the ones being discarded. Consider concrete: though 98% is recycled and used as roadbed gravel, there's more discarded concrete than there are roads that need gravel.

Then there's the problem of illegally disposed construction waste, which is estimated to account for 70% of all illegally discarded waste. The construction sector is also a major CO2 emitter. In 2011, Japanese manufacturing and construction emitted 244.78 million metric tons of carbon dioxide, compared with 587 million from manufacturing and construction in the US in 2010. Last year, Japan reneged on its pledge to cut its CO2 emissions by 25% compared with the 2005 level, instead announcing a 3.8% reduction target by 2020.

The irony is that unlike their post-war hastily erected forerunners, today's homes are sometimes well built and could easily last for several more decades. "Japan has a very efficient and sustainable way of mass-producing timber homes that are very good and can even withstand earthquakes," notes Townsend. "And Japan is a heavily forested country, but it imports the wood, which is in itself unsustainable." Many other houses, though, are rather logically built using less robust materials as they won't have to last long anyway."

The solution, argues Townsend, is for the government to stop promoting the dream of home ownership for everyone. Several years ago, Japan's parliament passed the so-called 200-year-home law, which reduces homeowners' taxes if their homes are built according to strict standards. The law might not be enough to change the disposable-home culture, but other small changes are under way: more condominiums, which can by definition not be demolished based on the desire of a single homeowner, are being built.

Recent research by Yoshida shows that homes built according to green building standards depreciate more slowly than regular ones, though they're more expensive to maintain. And renovation companies have spotted a market in promoting longer-lasting homes for the sake of the environment. As Yoshida notes: "We know that we can move towards a better world with less construction."

> via The Guardian