The article represents a study on the methods of calculation and evaluation of the properties of existing masonry, either by the method of testing the cores extracted from the masonry, or by the in-situ use of flat presses. The paper describes in parallel the two test methods along with the results obtained after performing them. At the same time, the method indicated in P100-3 / 2008 is analyzed by calculating the properties of the existing masonry starting from the properties of the bricks and mortar. The aim is to highlight the limitations of regulation P100-3 / 2008 in this regard. Finally, a case study on the expertise of Casa Vernescu is presented. When performing the expertise, the indications P100-3 / 2008, of annex G of P100-3 / 2008 and of the normative MP025 / 2004 were followed.