Prefabricated building panel

An assembly of extruded thermoplastic structural components for use in the construction of the upright side walls and roofing of a building, each structural component including an elongated rigid sheet member provided with at least two integral lengthwise edgewise rail members, said structural components including first and third flat wall structural components and second and fourth elbowed corner structural components, wherein the second elbowed corner structural components are provided with at least three integral lengthwise rail members, and wherein a few of said structural components are releasably slidingly interlocked with one another about their said rail members, without tools being required, to form hollow elongated panels wherein each said hollow panel defines a main body, including a flat exterior face and a flat interior face, and circumscribing a generally closed inner enclosure cell, said inner cell for receiving concrete to be poured and said hollow panel body adapted to withstand the load of a column of concrete poured therein;

• said sliding interlock engagement between said few structural components forming said hollow panels defining continuous lengthwise adjustment means for one said structural component relative to the other of said few structural components, said hollow panels releasably interlocking with adjoining hollow panels successively to form a continuous wall structure;
• and wherein said structural components in their disassembled state released from one another are compactly stackable in the smallest volume of storage whereby shipping costs from the home country manufacture to the local building site are very low.