| A Mobile Home is an engineered dwelling which is mostly assembled before it arrives at the site of installation. In modern times, you are required to lay down concrete before installing the home; The concrete supports jacks which in turn support the home.
Mobile homes have been made from various materials over time. In the 1960s and 1970s the most common construction was to have a steel backbone chassis/understructure, with ribs approaching the outer dimensions of the coach. Joists and framing are made of wood, with interior paneling of laminated compression board, and an exterior skin made of aluminum. While the chassis has changed little, and joists are still generally made of wood, the homes often now sport wood siding, and sometimes are framed in steel or aluminum.
Because a mobile home is legally considered to be an engineered home, you cannot legally make changes to the home without drafting some sort of plan which meets local building code criteria. This complicates the process of getting a permit to modify, remodel, or add on to your mobile home.
Mobile homes come in various widths, from single to triple wide, and even in two story models. Most new mobile homes are (at least from the outside) indistinguishable from a traditionally erected dwelling, and even have a concrete perimeter wall poured to resemble a classic foundation. | 
