Abstract: A modular habitation structure such as would be used in constructing a multi-room, multi-story building is disclosed. The modular structures includes floor framing formed from sections of structural support members such as steel channel beams securely interconnected to define the outline of a desired room shape. Upright sheet metal wall panels are fixed at their respective lower ends to the support members and at their respective height dimensions to each other to define the side enclosures of the room. A ceiling member of the same construction as the wall members is rigidly fixed to the upper portions of each of the wall members. The wall members, floor framing and ceiling are constructed and arranged and interconnected with each other to form a unitary, integral construction having a vertical load bearing capacity of a predetermined value greater than the weight of one completely constructed room and lateral force bearing capacity above a predetermined value.