In the Colonial Era, porches were typically small gabled extensions to cover the entrance to a home. When supported by columns they would be referred to as a portico. A small, covered entry or hooded door flanked by benches was called a stoop, from the Dutch word “stoep” for step.
In the late-18th and early-19th centuries longer shed-roof porches became more common, particularly in larger, wealthier areas. Formal colonnades in classical orders distinguished public buildings, grand homes, and hotels.
Throughout the 19th century the role of porches changed from largely utilitarian to a useful and transitional space, reflecting shifts in American society. Industrialization led to increased leisure time for many Americans. The mass production of goods and availability of pattern books made it easier and more affordable to build a decorative porch. In the second half of the century, the porch became an extension of the home, like an outdoor parlor.
Sleeping porches became popular at the turn of the 20th century as the hygiene movement promoted fresh air as a cure for ill health. Subsequently, innovations during the 20th century led to the decline of porches; automobiles allowed for easier travel to leisure and social activities outside of the home. Air conditioning, television and, more recently, computers have led to increased indoor leisure and social activities. Housing styles after WWII began to omit front porches in lieu of backyard patios and decks.
Porches of North America by Thomas Durant Visser
Get Your House Right: Architectural Elements to Use & Avoid by Marianne Cusato