Tract housing came about in the 1940s when the demand for cheap housing skyrocketed.
Economies of scale meant that large numbers of identical houses could be built in a "cookie cutter" fashion faster and more cheaply to fulfill the growing demand. Developers would purchase a dozen or more adjacent lots and conduct the building construction as an assembly-line process. Tract housing development makes use of few architectural designs, and labor costs are reduced because workers need to learn the skills and movements of constructing only those designs rather than repeat the
learning curve. In addition, as all houses in the
development will be built at the same time, the cost of purchasing and transporting building supplies may be reduced due to
economies of scale. Components such as
roof trusses,
plumbing, and stair systems are often
prefabricated in factories and installed on-site. This allows builders to offer lower prices, which in turn can make houses affordable to a larger percentage of the population. Early tract houses were often identical, but many tracts since the late 20th century have several designs and other variations in footprint, roof form, and materials, along with options such as garage bays, for a more diverse appearance. ==Suburbs==