Unreinforced masonry walls (URM) are structural elements usually observed in heritage buildings in Chile. The assessment of the elastic properties of this kind of structures is generally a challenging task, because of its orthotropic behaviour and the difficulties to extract and to handle in situ samples for destructive experimental tests. The study presented here aims to estimate the elastic mechanical properties of URM walls by applying vibration based non-destructive techniques. A representative segment of URM wall was built in the laboratory and subjected to a series modal tests using low energy impacts as excitation source. Modal properties of the wall were estimated through Enhanced Frequency Domain Decomposition (EFDD) and Stochastic Subspace Identification (SSI) methods. An orthotropic finite element model of the wall was successively updating through global sensitivity analysis techniques until the differences between experimental and numerically simulated modal properties were minimal. The results suggest that this approach can be extended to more complicated structural configurations.