A housing structure includes a first plurality of wall panels which form a lower course and a second plurality of wall panels which form an upper course. Each of the wall portions is generally rectangular and includes integrally formed interlocking portions which facilitate attachment of adjacent lateral edges of the wall portions of the first plurality to each other. Integrally formed interlocking portions facilitate attachment of the panels in the lower course to the panels in the upper course. In addition, rectangular roof panels are provided to enclose the housing structure. The interlocking portions enable the panels to slide into an interlocked engagement configuration thereby forming a rigid structure without the need for tools.