Abstract: A reusable modular housing system has a gridded structure comprising reusable components with dimensions corresponding to a two-unit system. The structure has floor and ceiling grids with dimensions that correspond to multiples of a first unit of measurement. The vertical beams that connect the floor and ceiling grids are spaced apart at dimensions that also correspond to multiples of the first unit of measurement. The structure has a variety of other components that can be coupled to the floor and ceiling grids and the vertical beams, and those other components have dimensions that correspond to a multiple of a second unit of measurement. Dimensions of the structure can vary, but each of the component parts can be detachably coupled into the gridded structure, so as to fit within the grid's dimensions based on respective multiples of the first unit of measurement and the second unit of measurement.