A flounder house is a term used in some areas to describe a type of house with a roof with a single slope, rather than the double slope of gabled roof. Some are oriented so that the shed roof runs perpendicular to the facade, in these tallest wall of the house lacks windows and doors. The house may align with a property edge, sit at the back of its lot, or align with other houses on its street. Others have a different number of apparent stories on the facade and the rear elevation, with the ridge line running parallel the facade.
Though modern examples exist, most flounder houses date from the 18th or 19th centuries. They can be found in cities in the United States from the Mississippi River Valley to the East Coast.
The flounder house's namesake is the similarly asymmetrical flounder fish.
The motivation for building flounder houses is debated. Common folklore follow one of three themes: "a result of an early restrictive building ordinance, the original owner's plan for future expansion, or a desire to reduce property taxes." In fact, shed roofed buildings are often simply the cheapest to construct.
Residents of various cities with shed-roofed houses believe that these houses are indigenous to their city.
Shed-roof houses can be found across the United States, including in St Louis, Missouri; Cincinnati, Ohio; Pittsburgh and Philadelphia, Pennsylvania; Charleston, South Carolina; Fredericksburg and Alexandria, Virginia; Baltimore, Maryland; New Castle, Delaware; and Boston, Massachusetts. The term "flounder", though, is not used in most of these locations.