An outbuilding, sometimes called an accessory building[1] or a dependency, is a building that is part of a residential or agricultural complex but detached from the main sleeping and eating areas. Outbuildings are generally used for some practical purpose, rather than decoration or purely for leisure (such as a pool house or a tree house), although luxury greenhouses such as orangeries or ferneries may also be considered outbuildings. This article is limited to buildings that would typically serve one property, separate from community-scale structures such as gristmills, water towers, fire towers, or parish granaries. Outbuildings are typically detached from the main structure, so places like wine cellars, root cellars and cheese caves may or may not be termed outbuildings depending on their placement. A buttery, on the other hand, is never an outbuilding because by definition is it is integrated into the main structure.
Separating these work spaces from the main home "removed heat, obnoxious odors, and offending vermin" and decreased the risk of house fires and food-borne illnesses.[2] The study of historical outbuildings also offers information about the lives of workers otherwise excluded from the history of a place, since one possible purpose of an outbuilding was to reinforce class boundaries.[3]
Outbuildings are typically constructed in a vernacular architectural style.[3] Outbuildings can be valuable resources for architectural historians as they may "offer insight unavailable in traditional documentary sources."[3] Architectural historian William Tishler argues that in addition to documenting outbuildings, researchers need to inspect attics and basements "because it's there that you see how things are put together."[4]
Researchers studying detached kitchens in Wiltshire identified some common characteristics of the outbuildings: non-standard floor plans, no large windows, location near the main house, footprint smaller than main house, and little or no interior ornamentation.[5]
Good farming and good outbuildings are invariably associated.
— Thomas Shaw, editor of Canadian Live Stock Journal (1888)[6]