The oldest still visible traces of domestic architecture in Pompeji show two construction techniques: opus quadratum (ashlar masonry) and opus africanum (limestone framework). These techniques were applied together in the same building, each for a specific purpose. Whereas ashlar masonry was always used in a consistent manner, the walls of limestone framework display a greater variety, which can be classified on the basis of construction techniques. This research has taken also into account the composition of the clay mortar which is typical for this period. After a relative chronology was...