Abstract: A prefabricated structure of at least two stories comprised of a vertically stacked modular core and interlocking system of panelized component room elements erected upon a monolithic concrete slab. The subject modular core is composed of three units each built upon a base pallet and featuring pre-finished walls, cabinets, appliances, fixtures, floor coverings and containing an integrated plumbing, mechanical and electrical system which services the dwelling. Said core modules and plurality of room elements are manufactured utilizing mass production techniques and transported to the building site. The lower core module contains a kitchen, central hallway, a portion of the staircase, and powder room facilities. Panelized room elements appended to the front and rear of the lower core form a living room and dining/den area.