House raising
House raising (house lifting, house jacking, barn jacking, building jacking) is the process of separating a building from its foundation and temporarily raising it with hydraulic screw jacks. The process is the first step in structure relocation in which the building is moved to a different location. House raising may also be a part of a renovation to build a foundation under an existing house or make a house larger by building a new floor level creating a two story house. Often employed in areas that are prone to flooding and storm damage, this process can be achieved through the use of either timber piles or helical piles. Once a house is raised and supported on cribbing, a new foundation can be constructed beneath it. After Hurricane Katrina and Hurricane Sandy large numbers of houses in parts of Louisiana, New York and New Jersey were raised to avoid future flooding.
Richmond District, San Francisco
To lure home buyers with promises of large houses while keeping prices low, homes were built with large basements (basements are an unusual feature in California because its weather permits shallower foundations) with the intention that the buyers could convert the basements into living space at their own volition. This essentially marketed a house as two stories, with the first story (basement) unfinished. This decision would prove to be ingenious as the 20th century evolved, as many basements were converted to garages. Some were converted with garages in the front and in-law units in the back.