factory built house - real estate - usa - This is manufactured home or a mobile home or a modular home that is fully furnished (with papered or painted walls or ceilings) The term factory built house does not apply to "panelized" or "kit" homes that are only partially completed and fabricated in a factory. Multistory homes, where the upper level is finished after the house is set on the foundation, are still considered factory built if the main level is finished in the factory.