(A) preparing wooden boards having ornamental outer face and being joined with fasteners; (B) attaching the boards to the inner walls of a mould for the walls to keep a certain distance from each other; (C) filling foaming resin agent under pressure in the space between the walls; (D) removing the mould from the wooden board walls having the hardened resin foam block in integrity to produce a prefabricated wall block, which is convenient for erection of house walls.
