## 1 Introduction  
The conservation of historical, cultural buildings is fundamental for ensuring the prolongation of their life and cultural witness of ancient culture and construction techniques; therefore, their conservation deserves special attention, because they are symbols of a culture and represent the local community as a whole. Usually they are under local, country, and UNESCO patronage and cannot be subject of invasive investigation.  
These concepts have been the object of many international guidelines, called Restoration Charters (Table 1), which outline the procedure for a correct conservation path [1].  
Conservation of heritage buildings must preserve \"Integrity\" and \"Authenticity\" of the building, and \"Vulnerability\" must be reduced.  
\begin{table}
\begin{tabular}{l} \hline
**Restoration Charters** \\ \hline Athens Charter, 1931 \\ Italian Charter for Restoration, 1932 \\ Venice Charter, 1964 \\ Italian Charter for Restoration, 1972 \\ Amsterdam Charter, 1975 \\ Washington Charter, 1987 \\ Nara Document of Authenticity, 1994 \\ Krakow Charter, 2000 \\ ISO 13822-2010, 2010 \\ ICOMOS Recommendation, 2010 \\ \hline \end{tabular}
\end{table}
Table 1: Restoration Charters.  
These themes had been addressed in the 3 rd Int. Conf. on Techniques, Measurements & Materials in Art&Archaeology2018, held in Jerusalem (Israel) and in the AIPnD National Conference held in 2019 at Milan (Italy).  
In Italy, the D.Lgs. 42/2004, art, 29, and the MIBAC 2011 \"Guidelines rules for conservation of cultural heritage and the reduction of seismic risk for cultural heritage buildings\" are in force. According to this Guidelines, the first step for a correct conservation work is the definition of the knowledge framework through the historical analysis, documents, geometry, and technical data. However, there is the necessity to acquire technical data on the masonry setting through non-destructive investigation techniques (NDT), such as photogrammetry, laser scan, thermography, georadar, sonic/ultrasonic tomography, Schmidt hammer, and seismic survey; or low destructive direct (LDT) inspections, such as DAC-Test, endoscopies, descaling of plasters, essays, small trenches, and flat-jack.  
Due to the rules on force and in prevision of a seismic vulnerability assessment, the Bargello Palace at Florence (Figure 1), Italy, has recently been the subject of extensive restoration work of the external curtains and of the inside of the Magdalena Chapel; in this frame it was possible to execute some investigation for defining materials and structures of the wall curtain of the back yard.  
Figure 1: (**a**) the Bargello place at Florence (Italy); (**b**) in foreground the tower and the front wing, back the porticos, covered courtyard, the rear wing, and the Magdalena Chapel site; (**c**) the interior of the Magdalena Chapel and the east wall with mural paintings by [PERSON].  
This study follows other similar studies on the medieval masonries of outstanding Florentine monumental cultural heritage buildings [2; 3; 4; 5], from which it summarizes the approach and its methodologies, that can now represent a reference standard for the application of NTD and LDT to future similar studies on ancient masonries.