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.
Basement
Generally, basements with only an emergency exit well do not count as walk-out. Walk-out basements with at-grade doors on one side typically are worth a lot more, but are more costly to construct since the foundation is still constructed to reach below the frost line. At-grade walk-out basements are on the door-side often used as livable space for the house, with the buried portion used for utilities and storage.