Abstract: A method of converting shipping containers containing factory equipment into a modular portable factory which comprises transporting the shipping containers to the factory site and aligning the containers in a side-by-side relation with their facing walls, to define the walls of the factory and floor of the factory. A roof structure spans over the top of the container to form top closure for the factory and access doors and stairways are provided in the factory. Shipping containers (main storage units) containing building materials are mounted on a foundation with the supply containers placed perpendicular, parallel or angled to the main storage units. The supply containers are movable by a supply track and the product moved by an assembly track, respectively, and turntables at the end of each of these tracks are operatively connected to the tracks to move the supplies or products in a desired direction.