PURPOSE: To obtain a brick substitute for wood block free from cracking, corrosion, etc., by melt molding a foamable plastic, followed by cutting the plastic to expose the layer of high ratio expansion.

CONSTITUTION: A plastic, e.g. polyethylene, polycarbonate, etc. incorporated with a blowing agent is melt molded to form the foamed article 1 having an expansion ratio of 2W3. The article 1 is then cut to expose the layer of high ratio expansion, thus forming a brick for fastening material easily attacted to the surfacing material 5 with the nail 4.