Opus reticulatum

Opus reticulatum (also known as reticulate work) is a facing used for concrete walls in Roman architecture from about the first century BCE to the early first century CE.^: 136–9 They were built using small pyramid shaped tuff, a volcanic stone embedded into a concrete core.^: 75–6 Reticulate work was also combined with a multitude of other building materials to provide polychrome colouring and other facings to form new techniques.^{: 260–4 : 189} Opus reticulatum was generally used in central and southern Italy with the exception being its rare appearance in Africa and Jericho.^{: 175 : 189} This was because of tuff's wider availability and ease of local transport in central Italy and Campania compared to other regions.^{: 73–4 : 189}

Reticulate work developed in response to the advent of opus caementicium and its predecessor, opus incertum.^: 136–45 This was to accommodate both the new building material and the growing demands of urbanisation in Rome through the creation of opus reticulatum, a method more uniform and accessible to unskilled labourers.^: 136–7 The need for quicker and easier techniques led to a decline in popularity allowing for the rise of brickwork as a more convenient alternative, especially after the Great Fire of 64 CE.^: 165–8

Opus reticulatum is important for understanding the choices the Romans made with their architecture while keeping in mind the architectural restraints and changes in their circumstances.^: 134–44 Reticulate work can also provide evidence of cross-cultural exchange between Rome and its correspondents through its usage outside of central and southern Italy.^: 175 Further, a written account from Vitruvius shows a Roman opinion on opus reticulatum and its significance in Roman culture. Along with other facings, the technique is also important for dating buildings in modern scholarship where there is an absence in explicit evidence to date the construction.^: 68–9