being shown in fig3 this comprising a nut 26 welded to a plate 27 in the corner stud 28 of each module the method of stacking one module on another is shown in fig6 which shows the interface along one side the upper frame 29 of the lower module being in abutting arrangement with the frame 30 of the upper module the concrete floor 31 of the upper module is supported on profiled steel decking 32 supported by the frame 30 fire proof boards 33 being underneath the decking 32 and also fire rated material 34 being positioned on the outer side of the frames 29 and 30 and inside frame 29 on the upper surface of the concrete floor 31 are positioned tiles 35 on grouting 36 stud 28 is attached by a cleat 37 skirting material 38 being positioned on each side of stud 28 also shown is the floor 39 of the adjoining floor of the building carpet 40 being positioned thereon the modules are superimposed one upon the other and joined together by positioning the base location 20 of the upper module into the lifting point of the lower module and bolting the two together which constitute a firm attachment means fig7 shows another view of one way of attaching the floor system to the wall frame the floor of each module comprising compressed fibro sheeting 41 bolted to the base of stud 28 mortar 36 being layed on the fibro sheeting to support the tiles 35 the fibro sheeting 41 is bolted by bolts 42 to base.