On Site Diagnostics for Architectural Conservation and Restoration

The topic of on site diagnostics for historical, monumental and vernacular architecture is characterized by a twofold difficulty, partially due to a sort of hiatus between the scientific community and a professional system. In fact, on one side universities and research centres produce advanced technologies, methodologies and procedures, but they are not always adequately disseminated among professionals and are sometimes inconsistent with some relevant criteria, such as feasibility and cost-effectiveness. On the other side, professionals, in the field of on site diagnostics for historical architectures, are holding a heritage, made of experiences and practice, which often is not enough shared and sometimes is contrasting with the limited possibilities to evaluate and verify the professional training and certification system, which seems too heterogeneous, if compared to other high scientific and technical professions, as is the case, for example, in medicine or engineering.
In this book, the diagnostic experiences are described, though, for logistical reasons, often briefly, following a systematic methodological approach, according to three of the main steps for the knowledge of historical buildings: anamnesis, diagnosis and prognosis, obviously with particular attention to the specifically diagnostic issues (diagnosis), but framed in the preliminary diagnostic plan and interpreted in the light of the performance, prefigured in the preliminary stages and connected to the visual inspection. That is why this book regards not only some experimental, unconventional and innovative diagnostic surveys and diagnostic experiences, carried out on particularly valuable monumental buildings under the historical-architectural point of view, but also ordinary and simple experiences in the field of professional diagnostic practice, where, however, it was possible to apply the methodology and the know-how, acquired and systematized in the performance of the experimental diagnostic surveys, often included in wider scientific research projects. This book is not exclusively addressing the scientific and academic community, but it also pursues the aim of disseminating in the professional system a heritage of rather varied experimental researches and practical experiences, but methodologically oriented toward a culture, which considers the design of diagnostic plans as a regulation criterion for quality control of professionals.

Leseprobe
Text Sample:
Chapter 1. Masonry buildings with timber floors and roofs:
1.a. Churches and monumental buildings:
St. Maria del Popolo Church, Rome-Italy:
Abstract:
This diagnostic survey is about the potential of thermographic mapping as support of historical and architectural investigation, to understand the constructive phases, stratifications and architectural palimpsest of St. Maria del Popolo Church in Rome-Italy, which is particularly complicated because result of many changes over time, and also because this very well known church is a relevant monument in the history of Italian architecture and art, because in ist construction and transformations prominent architects worked, including Donato Bramante, Raffaello, Gian Lorenzo Bernini and Carlo Fontana, and it preserve several art works of great artists, including Pinturicchio, Annibale Carracci, Caravaggio, Sebastiano del Piombo and many others.
A. Anamnesis:
This diagnostic investigation consists of some thermographic tests onthe inner walls of the apse and on the main façade of St. Maria del Popolo Church in Rome-Italy, built between 1473 and 1477 by the architect Andrea Bregno, on the former site of the mausoleum of Domitii Enobarbi, where the emperor Nero was buried and best known for the subsequent interventions, including in the early 1600sthe choir, re-designed by Donato Bramante and the Chigi Chapel, designed by Raffaello, in the second half of 1600 the Baroque restoration by Gian Lorenzo Bernini and the reconfiguration of the Cybo Chapel by Carlo Fontana. The purpose of this investigation is to collect useful data for the identification of possible niches, now hidden in the walls, and for understanding construction techniques and conservative conditions of the walls. Seven thermography on the inner walls of the apse and six thermography on the main façade were performed, using three different thermal cameras.
B. Diagnosis:
The diagnostic survey was conducted inside the church and on the main façade of St. Maria del Popolo Church, in order to collect relevant data to identify possible niches, currently filled and hidden by plaster, a general evaluation of the structural and conservative issue and for better understanding the constructive phases of the apses. This survey was conducted within the church without a preliminary indoor heating; this resulted in a low heat emissive capacity of internal surfaces and, consequently, a low possibility to detect thermal anomalies, as indicator of the presence of possible niches under the plaster. It was, however, made a detailed thermal mapping, with the detection of three areas affected by thermal anomalies, which suggests that there is a niche now filled and covered, on the north side, which probably dates back to the reconstruction and reconfiguration phase of the choir, designed by Donato Bramante. At the end a thermal mapping on the main façade was performed, which was exposed to direct sunlight, so the differential temperature allowed us a more sensitive thermal mapping. This thermography showed a set of different anomalies, including the infilling of a fanlight, perhaps relating to the intervention phase designed by Gian Lorenzo Bernini, and some totally or partially detached slabs of travertine of the stone facing, suggesting the need for a preventive intervention. This simple thermographic mapping produced two types of results:- first of all it provided useful information for the study of the architectural history and transformations of a monument, which is one of the most interesting in the history of Italian architecture, because largely stratified over time and therefore difficult to analyse from the point of view of ist modifications and alterations;- secondly it could provide some suggestions with respect ist conservative condition, especially the detachment of some stone slabs in the stone facing of the main façade, which is a degradation difficult to recognize during a visual inspection, suggest