A cardboard cathedral in New Zealand designed by Shigeru Ban.

Architects, Ban notes, are lucky because they always work for people who are happy - as people generally are when they're building a house. But has always felt that architects need to play a broader social role.

"After I became an architect I was very disappointed in our profession," he says, "because we are mostly always working for privileged people, with power and money. So I thought that architects needed to have more of a social role. I thought we could use our experience and our knowledge for people who need help in a natural or man-made disaster. Even something like temporary housing, we can make more it comfortable and more beautiful."

In times of disaster, building materials can be difficult and expensive to procure. That's why, Ban says, his favorite building material is something most people throw out: cardboard tubes.

"Even in Kigali, Rwanda, when I was building shelters, I found them," he says. "I'm not inventing anything new. I'm just using existing material differently."

In 2011, when Japan was rocked by an earthquake and tsunami, Ban first created partitions to help families keep their privacy in shelters like gymnasiums. Then he built, on the grounds of a baseball stadium, a three-story temporary shelter to house 19 families.

After the Kobe earthquake of 1995, he built a "Paper Church" which remained there for 10 years, he says, because of the public's affection for it. Ultimately it was dismantled to make way for a permanent structure and rebuilt in Taiwan as a community center.

"Even a building that is made of paper can be permanent, as long as people love it," he says. "And even a concrete building can be temporary, as we see in earthquakes."