Coffered ceilings in the churches of Rome, from the 15th to the 20th century

The contribution concerns the coffered ceilings in Roman churches, which have been built between the mid-fifteenth and the mid-twentieth century and represent ornamental components of great value. The coffered ceilings still visible today are approximately sixty; many others have been demolished or destroyed by calamities through the time. The attention on the subject revived after the collapse in the church of San Giuseppe dei Falegnami occurred in August 2018; the event highlighted the vulnerability of the coffered ceilings and a lack of historical and technological knowledge regarding individual cases. Referring to the architectural treatises on the subject, this article focuses on the early-nineteenth-century texts by Jean-Baptiste Rondelet and Giuseppe Valadier, illustrating two different criteria in creating coffered ceilings. In the first one, the coffered ceilings are directly connected to the roof trusses, providing for the lining of the tie beams. In the second one, the coffered panels are nailed to wooden frames hanging from purlins placed over the tie beams. Both construction methods can be found in the coffered ceilings of Rome, but most of the cases refer to the second system. Thus, the contribution delves into the construction process in detail and focuses on the arrangement of the elements, reporting the analysis of some study cases, based on direct checks and surveys. In this regard, knowledge of the extrados of the ceilings is crucial foreseeing possible conservation works, allowing to avoid the risk of inappropriate restoration or replacement of original elements.