Could this be the solution to Hong Kong's housing crisis?

Hong Kong has one of the worst housing crises in the world, with property prices so high that a single parking spot sold for $664,000 last year and all but the wealthiest are stuck renting tiny apartments with an ever-proliferating range of colorful names: micro-flats, nano apartments, coffin apartments, and cage homes.

It's gotten so bad that the city has been ranked the least affordable city for housing in the world for eight years running, according to the Annual Demographia International Housing Affordability Survey.

"We are facing a tangible affordability problem in our cities," architect James Law told Business Insider. "It is almost beyond the reach of most people to afford to live in a proper home in Hong Kong."

Law thinks he may have a solution: a retro-fitted concrete water pipe.

The idea came to him last August when he was overseeing a construction site. He noticed some leftover concrete pipes at the site and found that they were large, strong, safe, and not being used. Law designed and built the prototype for the O-Pod in less than a month.

The O-Pod wasn't Law's first "crazy project" — he tries to challenge himself with one each year — but it is the first to garner attention across the world. Within months, the O-Pod had been written up in the New Y0rk Times, the South China Morning Post, BBC News, and Business Insider. And he has received inquiries about the design from firms in New Zealand, South Africa and Hawaii.

In April, Law signed a contract with a developer in Shenzhen, China to build the first O-Pod complex.

"​The big dream of mine is not necessarily me doing it, but a global community of people who share the same values using this as an open source design to share around the world," Law said.

"If we can work with governments, and even private landowners and manufacturers, we could very cheaply build the O-Pods, and we could rent them out very cheaply to young people who are struggling to afford housing."

Law recently gave us a tour of the prototype and revealed where he wants to take it from here. Here's what it was like:

The prototype of the O-Pod is located beneath a bridge in Kwun Tong, a former manufacturing area in East Kowloon.

The O-Pod is made from two sections of concrete drain pipe and has a living space of around 100 square feet. Law's goal for the O-Pod was to create something that was cheap, easily maintained, and quickly built.

Key to keeping the costs down is using a pre-manufactured product, according to Law.

"When you build it yourself, it's expensive and requires labor, quality control, and testing," Law said.

But because the O-Pod uses concrete water pipes, which are already being mass-manufactured, they are "low-cost, well-engineered, and being concrete, these pipes have good insulation properties."

Designed to go underground, they are also extremely strong and can be stacked on top of each other to immediately become a building, without having to build additional ‘bookcase’ structures, columns and beams, etc [as is the case with shipping containers].”

The O-Pod feels bright and spacious when you step inside. Though the floor space is 100 square feet, the curved walls and the tilted lights make it feel much bigger.

It comes outfitted with a book shelves and a desk, which can also double as a dining table. While future iterations of the O-Pod will likely evolve, Law believes strongly in building homes that adapt to the users' needs and furniture that serves multiple purposes.

"Because of the pressure caused by the growth of cities, we have to get more out of a smaller space," Law explained. "We need to make architecture that is more responsive to the actual conditions and needs of people."

Law tries to thread technology through every architectural project he takes on. Eventually, he imagines homes will be like "Iron Man" armor in that they augment the capabilities of its inhabitants. One small example: He imagines future O-Pods would be ideal smart homes, with everything controlled via one's smartphone.

The O-Pod includes a sofa that folds out into a bed, as well as shelves, a mini-fridge, a microwave, and an air conditioner.

There's also a separate room for bathroom with a toilet and a shower. The bathroom was larger than any of the ones in the apartments where I stayed in Hong Kong.

For more on Hong Kong's tiny bathrooms, check out my article here.

While each tube home would cost $15,000, Law is hoping to work with governments and private landowners to create innovative models to help young Hong Kongers get a leg up.

Ideally, according to Law, the O-Pod would be rented out for 3,000 Hong Kong Dollars per month, or about $400. Two-thirds of that money would be invested in a savings account for the tenant, while one-third would go towards maintaining the homes.

By investing two-thirds of tenants' rent and giving the "nest egg" back to them once they move out, Law hopes that the O-Pod could be a place where young people "build hope."

The endless rental cycle can be "very debilitating and sapping on the optimism of young people," he said.

Law suggested that the 3,000 HKD price came from the global rule of thumb that one-third of one's income should go to rent in order to consider housing to be affordable. Most recent university graduates in Hong Kong earn an average salary of 14,000 HKD per month. After taxes, that comes out to around 10,000 HKD.

Three thousand HKD per month would be extremely low for Hong Kong's rental market where rent for an apartment rarely goes below 10,000 HKD and many sub-divided flats run for between 6,000-8,000 HKD.

"This was never meant to be a commercial profit kind of business. This was much more like something I wanted to do to help people," Law said.

There have been numerous attempts in recent years to create low-cost housing solutions. Perhaps the most persistent design is retrofitting a shipping container, like this one which has been selling on Amazon since November for $36,000.

Other architectural firms and creative agencies have also taken a stab at the design problem. Last year, Oslo and New York City-based Framlab developed Homed, an arrangment of hexagonal pods that could be attached to buildings to house the homeless.

In 2015, the IKEA Foundation developed an ultra low-cost housing solution for refugees that could last for up to three years.

The ALPOD, the Ecocapsule, and the PopUp House are all low-cost environmentally friendly housing designs that have popped up in recent years.

But Law said that many of these designs, in particular the shipping containers, do a poor job of accounting for fire safety. Because concrete water pipes are engineered to be underground, he said, they are super safe, fire-proof, and water-proof.

Part of the philosophy behind the O-Pods is the idea that cities need to be built with the understanding that neighborhoods often have changing needs. The O-Pods can be stacked just about anywhere — under highways, between buildings, or in office parks.

For example, the Kwun Tong district, where the O-Pod prototype is located, used to be a major manufacturing hub. As manufacturing has left the city, it has left behind dozens of empty factory buildings. Knocking the buildings down would be expensive and not environmentally friendly.

If in the future, buildings were constructed to be more modular and flexible, a neighborhood's changing character wouldn't be as much of an issue, according to Law. Simply deconstruct the O-Pod complex and move it to a new area that needs the housing.

"Then we can keep changing with the times," he said.

In March, the O-Pod had its first resident for a single night. The South China Morning Post's Alkina Reinfrank stayed in the O-Pod on one of Hong Kong's chilliest nights.

"Despite the cold and the noise disturbing my sleep, I found its design to be innovative and believe it can provide temporary accommodation," Reinfrank wrote in March.

"However, I would say people could only live in one for a few months, rather than two years, because of its lack of storage space."

The O-Pod is still a work in progress, according to Law, who says he's working to improve the design while maintaining its low cost and simplicity.

Law said that future iterations of the O-Pod will improve on the design issues brought up by Reinfrank. Currently, the prototype has minimal storage space and only a microwave for a kitchen. While it is not unusual for a Hong Kong kitchen to be bare-bones, he understands that the O-Pod will likely need to add some additional equipment.

Among the issues: soundproofing, insulation, and weight. While the tubes are transportable, their heavy weight needs to be accounted for when choosing housing sites, according to Law.

Law suggested that the O-Pods' thick concrete shells made them as soundproof as a concrete building. But during her night at the O-Pod, Reinfrank complained that persistent street noise kept her awake.

One of the biggest design challenges, according to Law, is designing curtains that work for the circle aperture of the tube. Otherwise, your whole life is visible to the street.

"Ultimately, we need to somehow find a way for people to want to stay a long time. This can't be like a hotel room. People need to feel like they can stay for a year or two," he said.

Future projects will include co-living facilities such as a communal living room, dining room, and kitchen, so that tenants don't feel stuck in the "tube homes" at all times.

While 100 square feet sounds small, it's actually double the average living space for Hong Kong's poorest residents, many of whom live in so-called "cage homes" or subdivided apartments.

According to a survey conducted by Kwai Chung Subdivided Flat Residents Alliance last year, the average living space for the city's poorest residents was about 50 square feet, about half the size of a parking space and equivalent to that of those living in shared dormitories in correctional facilities.

Nano apartments — apartments with a square footage less than 200— are becoming more popular due to their affordability, according to the South China Morning Post. But affordability is a relative term. Many sell for as much as $500,000.

Law said that he is working on the potential for a five-meter diameter cube for families that could add a lofted sleeping area.

In April, Law signed an agreement to build the first O-Pod complex at 289 Digitland, a new development in Shenzhen, China.

289 Digitland, a development that provides office space and housing for design companies and artists, will develop the O-Pods as a kind of incubator for young, upstart designers struggling to afford the rent in Shenzhen.

The complex will feature six O-Pods stacked into a 3-2-1 pyramid and the tubes will be slightly bigger than the prototype in Hong Kong, measuring 3 meters in diameter rather than 2.5 meters.

Rent will be subsidized with the aim that those that stay at the space will eventually be able to move into the main Digitland complex.

It is due to open in July.