Abstract: There is provided a structure that is a prefabricated (or systems-built) building space including a floor assembly, modular wall assemblies, and a roof assembly. The structure may at any time be connected to one or more other structures or prefabricated room extensions to form integrated building spaces. The structure is attached in a semi-permanent connection to a helical pier foundation assembly. The structure can include a locking mechanism adapted to be removably fastened to the floor assembly and the foundation assembly.

Abstract: A refrigerator includes a main body including a plurality of wall modules, a storeroom disposed inside the main body, and a door arranged to open or close the storeroom. The plurality of wall modules include a first wall module having a concave portion and a second wall module having a convex portion engaged with the concave portion. The convex portion includes an insulation filling space in which insulation is filled, and a fastening groove. A fastening member is inserted into the fastening groove so as to be fastened to the first wall module and the second wall module.