Abstract: A small, heavy duty, transportable building having pre-manufactured panel assemblies made out of magnesium oxide for the floor, wall and roof that are quickly fastened together, on site, using common metal screws. All building materials are inorganic for extreme mold and mildew resistance. Furthermore, the building panels are configured and fastened together for inherent insulative fire and flood resistant properties. Commercial metal strut forms an economic protective perimeter around the magnesium oxide surface panels, and offer a fastening means to adjoining panels. The uses of the building (bunker, enclosure, shelter, shed, little-house, etc. . . . ) are myriad and not intended to be limited in usefulness. In addition, the building configurations and square footage options are limitless, single wide building ways, storied if desired. The design also allows manufacturing of the panel assemblies with common, hand tools, power tools, and welding equipment. No crane is needed for building erection.