History
Limited amounts of prefabricated components date back to ancient times. Mesopotamian’s used burnt clay bricks. Romans utilized concrete molds for aqueducts and tunnels and William the Conqueror conquered the concept. There were movable modular buildings for industry, defense, and even hospitals. However, hand construction was the norm for the vast majority of houses and buildings.
That changed in 1908 when Sears Roebuck released a new item in their catalog, houses. People could order all the parts and pieces required to build entire high-quality homes and they’d come in a kit. Sears brought standardized parts, the “American Manufacturing Method” (invented by the French) to houses.
“For $1,062 we will furnish all the material to build this Eight-Room House, consisting of Lumber, Lath, Shingles, Mill Work, Siding, Flooring, Ceiling, Finishing Lumber, Building Paper, Pipe, Gutter, Sash Weights, Hardware and Painting Material,” reads a typical ad from 1908. All houses also included free architectural plans to aid in permitting.
Some houses were modest though many were large and there was at least one mansion.

Sears discontinued selling kit houses in 1940 after selling about 70,000 houses.
Modern Day
However, the idea of modular building components remains. Today, doors routinely come with frames for installation. Hand-built trusses, that hold up roofs, are virtually unheard because factory-made ones are safer and cost less. Windows routinely come preassembled and, in some places, hand-built windows are illegal for safety reasons. Countless components of modern houses, especially in the US but also elsewhere are built at factories, not job sites.
Besides prefabricated house parts, entire prefabricated houses and buildings still exist.
In addition to prefabricated parts, there are also “modular” construction units. These function like building blocks, with various parts of houses and buildings fitting together. Modular buildings theoretically cost less than one-off construction but have higher quality since the pieces are built in tightly controlled factories.
Hotel chain Citizen M uses prefabricated modules to build entire hotels, including a 300-room hotel in New York City. The Chinese famously built the 57-story “J57 Mini Sky City” in 19 days using modules.