A prefabricated structure comprises a shell including a shell frame and an extension deployable from the shell, the extension including an extension frame. The shell frame comprises a floor support including a plurality of slotted beams extending between and transverse to the floor beams, a roof support, and a plurality of columns extending between the floor support and the roof support. The extension frame comprises a floor support, a roof support with an extension roof, and a plurality of columns extending between the floor support and the roof support, wherein the slotted beams of the shell floor support each include a slot through which a column connected between an extension floor beam and an extension roof extends when the extension is nested within the shell in an undeployed position.