permit the inclusion therein of electrical or plumbing conduits and boxes 15 15a as shown in fig3 similarly basic panel 11 may be modified to include as part of its structure a door frame as illustrated by panel 12 or a window frame as illustrated by panel 13 also edge portions of basic panels may be modified to provide corner panels such as 16 except for the above mentioned details the basic structure of all panels 11 16 is identical or substantially identical a panel embodying the present invention may be formed of a castable material that is initially plastic and which hardens after setting such as concrete synthetic resinous materials cement and the like in accordance with the present invention the outer surfaces of such a panel can be of any desired texture and or may include any design that may be desired from an aesthetic or architectural viewpoint the material from which the panel is formed may be or may contain a foamed or foamable material such as polyurethane and the like it is desirable that a material utilized to form a panel in accordance with the present invention be one having properties both physical and chemical that are stable and are not subject to deterioration with age as a result of decay or a similar defect it is also desirable that such material be fire resistant or incombustible and that it be resistant to and unattractive to ants termites and the like as well as other pests on the basis of information presently available a panel embodying the present invention preferably is formed of a homogenous.