Question

Thomas Edison proposed and constructed an unusual type of house. Ten of his prototype houses remain standing and occupied in New Jersey. What was unusual about his houses?

Answer

The houses were made from a single pour of concrete into a cast iron mold. His first house was constructed in 1912 using 3/4-inch- (1.9-centimeter-) thick cast-iron molds. The pour lasted only 6 hours. But the costly 250,000- to 450,000-pound (113,000- to 204,000-kilogram) molds were tied up for at least two weeks for assembly, cure time, and disassembly.