Building cluster of a plurality of building units

A building cluster comprising a plurality of building units, each said building unit forming at least one room at least when connected to one or more adjacent building units, each said building unit being of a width and length selected from a plurality of a modular unit dimension, said plurality of a modular unit dimension being arranged in two directions as a horizontal modular grid, each said building units being arranged to be joined together to form said building cluster so that the center line of any joint between said building units coincides with any selected grid line of said modular grid and so that any wall between any two adjacent said rooms formed by any two adjacent said building units is a wall common to both said building units, and is further arranged so that the center line of said wall coincides with the center line of any said joint between said building units and with said selected line of said modular grid, each said building unit being constructed separately from any other building unit in said building cluster and comprising a stressed skin floor member and a stressed skin roof member both the same length and width, and a plurality of wall panel members on at least two sides of said separately constructed building unit, said wall panel members being disposed between said floor member and said roof member and removably connected thereto by means of lug members inserted on the center line of the top and bottom edges of said wall panel members, and removably connected to the edges of said floor member and said roof member in which at least some of which removable connections of said lugs to the edges of said floor members and said roof members are adapted to resist shear forces due to side sway or lozenging forces on said building unit without changing the configuration of said wall panel members, said wall panel members being spaced apart from and connected to each other in their vertical edges by means of removable spacing members such that at the connection of at least two said wall panel members a continuous cavity is formed the least dimension of which is at least concident with the thickness of any said wall panel member arranged to enable changes selected from removal and addition of any said wall panel member without disturbing any other said wall panel member in the building unit and without disturbing any electrical wires in the cavity, the relationship of the edges of said floor members and said roof members and said wall panel members to said modular grid being such that where M represents said modular unit dimension and n represents any whole number and nM represents any plurality of said modular unit dimension, and where d represents the spaced distance apart of the edges of any two adjacent said floor members or the edges of any two adjacent roof members and coincides with the thickness of any one said lug, t represents the thickness of any one said wall panel member, and is always greater than d, then any said floor member and any said roof member has a length or width of nM-d, and any said wall panel member has a width of no greater than nM-t and no less than nM-2t so that any said floor member or any said roof member or any said wall panel members has a fixed relationship of its vertical edges to said modular grid regardless of the plurality of modular unit dimensions selected for its horizontal dimensions, and so that the intersection of the center lines of at least three said wall panel members, when one said wall panel members is at right angles to the other two said wall panel members, will concide with the center line of the joint between at least two building units and with the intersection of the lines of said horizontal modular grid with the vertical edges of these panels a fixed distance away from said intersection so that such vertical edges define a space between the panels.