The principal materials for construction were tufa, schist and a hard limestone, with tufa being the commonest stone used at the site. The tufa is very fragile and the cut tufa stones have frequently crumbled to dust. The infill used within the structures is quite inconsistent and consists of stone, earth and clay. The mortar used in construction was of low quality, with little lime, using only a hard clay that was particularly vulnerable to water damage, causing the stucco facing to come away from the structures and resulting in their complete collapse.