Final answer:
Three key changes in house building during the 20th century were the introduction of prefabrication, the shift towards open floor plans, and the adoption of modern materials and techniques.
Step-by-step explanation:
Three key changes in house building during the 20th century are:
- Introduction of prefabrication: In the 1920s, architect Frank Lloyd Wright designed a concrete block system that allowed builders to order premade and easily assembled blocks with customizable color and texture. This revolutionized construction methods and made the building process more efficient.
- Shift towards open floor plans: In the 1930s, Wright designed houses with open floor plans, incorporating the kitchen into the dining room and creating a central living area. This reflected changing social dynamics and the diminishing need for servants in American households.
- Adoption of modern materials and techniques: The use of steel, plate glass, and other industrially produced materials became more prevalent in the 20th century. This led to the development of bold structural frames, clean lines, and plain or shiny surfaces in modern architecture.