Faragola and Canusium potters used Ca-rich clays-widely available nearby-for the production of building materials. The clayey materials were used as received, before being fired in the local kilns at temperatures between 600 and~1000°C. No technological distinctions were made in relation to the type of object to be produced (tile, brick, etc). The investigated productions are compositionally distinguishable from both coarse wares for cooking and fine table ware produced in the same archaeological sites. A fine clayey material, very similar to that used for table ware, was supplied for the production of these building materials, which are chemically, mineralogically and petrographically very similar among themselves. Hence, the Faragola and Canusium bricks and tiles cannot be easily discriminated but the presence/ absence of volcanites and volcanic glass represents an effective discriminating factor, able to indicate areas of different supplies within two main deposits: the Pleistocene marine and alluvial terraced deposits, typical of northern Apulia.