Galvalum which is an iron-based material with a layer of aluminum and zinc. Because it is made from iron, galvalum is very suitable for use as a structural material, especially as a sturdy and strong roof truss. Galvalum which functions as an outdoor roofing material, gutters, fences and other necessities including large buildings or houses. apart from that termites are the no.1 enemy of wood. There have often been cases of roof collapse due to the wood roof truss being eaten by termites. This will not happen if your roof frame uses galvalume material.