“[Roof House] looks simple but it’s not. For example, we made the rooftop inclined. This lets the rain water down but it serves another function as well… By doing some studies about public squares, we found that the most popular squares have an incline, such as Pompidou Center [in Paris]…. But if you have a famous flat square such as [London's] Trafalgar Sq., people tend to stay off to the sides and not go into the middle.” Tezuka says that his design Roof House has illustrated this idea in a real world scenario, citing the family’s propensity to sit or lie down across all areas of the roof.
Tezuka says that his Roof House project also illustrates a second important character of his design philosophy, which is to incorporate the surrounding natural environment into the home experience as thoroughly as possible. “Wherever you find a human being,” Tezuka says, “we are supposed to be able to cope with the nature around us. Whether you go to Stockholm, where either half of each year is quite comfortable, or to China where most of the places have bad weather, we should be able to use that nature as it should be. [Of course] we want to change nature so we can live comfortably all the time, but we are not able to do that so we need to adjust our human being self.”
This last point Tezuka emphasizes as fundamental to his design philosophy. Tezuka holds firm the conviction that almost any weather can be perceived as comfortable by the human body and that the trick lies not in the human body’s adaptability, but in the mind’s ability to perceive climate in a different light. As proof of his theory, Tezuka points to the extreme temperatures of many popular vacation spots. “I always use an example of people going to the beach in the summer,” he says. “You might say you want to be in air conditioning, but still you go to the beach even though the surface is 50 degrees Celsius. In the winter you go skiing, but the ski resort is very cold… My point is you need a whole existence, not just a temperature. As long as there’s some kind of fun or joy coming with that nature, the human being is strong enough to cope with all these kinds of temperatures. So my rule as an architect is to create and intone a joyful environment for human beings where people cope with change of temperature.” He also mentions that as a resident of Japan, utilizing this principle in architectural endeavors is especially important since Japan is a country marked by extreme seasonal changes from freezing winters to boiling summers.