The floorpan is a large sheet metal stamping that often incorporates several smaller

welded Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as bra ...

stampings to form the floor of a large

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wat ...

and the position of its external and structural panels. In the case of

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

designs, the floorpan is the most important metal part establishing the

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

, body, and thus the car's size. It serves as the foundation of most of the structural and mechanical components of a unibody automobile to which the

powertrain A drivetrain (also frequently spelled as drive train or sometimes drive-train) is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components o ...

, suspension system, and other parts are attached. The term is also applied to the smaller stamped panels that form the floors inside a vehicle as well as the bottom of the trunk.

See also