Tabique construction is one of the main Portuguese traditional building techniques that use earth based building materials. It is peculiar building technique which uses corn's cob as a filling material for the external tabique walls. The existing tabique construction in Trás-os-Montes e Alto Douro region of northeast Portugal was studied to learn from it for modern day construction. The research showed that corn's cob, an agricultural waste, has the potential to be used as a sustainable building material for thermal insulation. An experimental work concluded that there are significant similarities between the corn's cob and the extruded polystyrene (XPS) material in terms of microstructure and chemical composition. Furthermore, the results obtained from an expeditious experimental thermal procedure indicate that the corn's cob may have adequate thermal properties for building purpose.