Abstract: The invention relates to a prefabricated building panel which may be used in particular as a flooring element. The prefabricated building panel is constituted by a block of insulating material, particularly an expanded polymer material and a framework formed of at least one stiffener or bearer element, joined to the insulating material to form a self-bearing insulating panel without a thermal bridge.According to the invention, the panel comprises at least one stiffener element embedded in the block of insulating material.The invention also includes a process suitable for making this panel.