Housing shortages affect both developed and developing countries, so entrepreneurs are trying to find new ways to solve the problem.
They're being assisted by 3-D printers, which are rapidly entering all levels of industry, including construction.
Last December in Nanjing, the Chinese 3-D Research Printing Institute opened an exhibition in a house built with elements created by a giant 3-D printer. The machine extrudes layer upon layer of concrete-based material, creating construction elements. That eliminates the need for large construction crews, saving money.
Ma Yih, chief executive of WinSun Engineering, said the three-story house was built in three days, mostly of recycled materials.
“We use urban construction waste, mine tailings and urban solid wastes as raw materials," he said. "We sort them by category, and we transform them into a special printing ink.”
Instead of waste material, architects in Amsterdam are experimenting with a mix of one-quarter plastic microfibers and three-quarters plant-based oil. They say traditional building construction is inefficient and creates a lot of pollution, while 3-D printing reduces waste and other costs.
Another advantage, said DUS Architects co-founder Hans Vermeulen, is the flexibility of 3-D printers.
“Digital fabrication allows us and allows customers to tweak designs into their own personal needs,” he said.
Vermeulen added that 3D-printed houses can easily be taken down and reassembled elsewhere.
In Nigeria, unavailability of cutting-edge technology does not discourage entrepreneurs in the search for innovative housing solutions.
Out of millions who live in shacks because traditionally built houses and apartments are too expensive, at least some will be able to save enough for a house that can be built in just seven days.
A company called Tempohousing uses shipping containers, made of corrugated fiberboard or steel. Managing partner Dele Ladipo said the company's fast construction attracts customers.
“Our solution, compared to traditional concrete, is about 25 to 30 percent cheaper than if you build the same structure using concrete,” he said.
Container walls are covered with insulating material and panels that hide electrical and plumbing installations. Steel rods provide a rigid structure, and roofs are covered by roofing material, but there is no need for bricks or concrete.
Although most of the customers are businesses and hotels, Ladipo said private clients are showing interest.
“The African mentality is changing a little bit," he said. "The cost of housing, cost of land, is so much now that everyone is looking for an alternative option.”
As traditionally built homes are still beyond reach for many, experts say only alternative building methods can hope to ease the enormous housing shortages in most of the world’s developing countries.