Finding optimal retrofit solutions for existing historical unreinforced masonry buildings presents an ongoing challenge in post-earthquake reconstructions. High costs of reconstruction and limits given by conservation guidelines require the least possible interventions with maximum effect. To this end, it is advantageous to adopt target retrofit solutions that strengthen only a few critical elements which contribute the most to the main failure mechanism of the building. How to effectively identify the critical elements to be retrofitted remains an open question. The present work aims to develop a simple framework for identification of critical elements by using nonlinear time-history analyses on a full spatial nonlinear building model, applying seismic damage analysis procedures and disaggregating the damage at wall and component scales. An unreinforced masonry building typology from the city of Zagreb, Croatia, is selected as a case study. A nonlinear building model is developed using Tremuri software and multiple stripe analysis is conducted. Damage analysis is performed using a modified Park and Ang damage index and a discrete physical damage scale for masonry components. The damage is then disaggregated by each element and each ground motion record across all intensity levels of ground shaking using a weighted damage parameter. Critical walls, storeys and directions are determined, as well as dominant failure mechanisms. Target retrofit strategies are explored which may be linked to damage disaggregation results, facilitating urban scale implementation.