OLOMOUC, CZECH REPUBLIC — RADIM KRALIK and his wife, Barbora Kralikova, live in a modern concrete box on top of a 1943 grain silo, a stark contrast to the neo-Gothic spires that dominate this small city about 175 miles east of Prague.

The unconventional home was inspired 30 years ago, in Communist-era Czechoslovakia, by a photo that belonged to Mr. Kralik’s father  an image of a traditional Bavarian house set on the roof of a high-rise.

“I was struck by the idea of putting disparate elements together, old-fashioned and modern, a crowded apartment building topped by a single home with an amazing view,” he said, but “I tucked away the memory of this photo in my mind and forgot about it until I saw this abandoned agricultural site.”

Mr. Kralik, 41, the owner of an advertising production company, bought the derelict structure 11 years ago for 300,000 koruna  what was then about $10,000  for his business; the side of the silo seemed like a good spot to put a billboard, he said. “Then I went to the top of it and thought this would be a great place to have a house.”