We have applied ultrasonic nondestructive techniques to gain information about the state of the first layers of a historical church dome wall. This may help in the restoration of the dome. Before the restoration, it can help us to find the areas where consolidation is required. After the restoration, it can help us to evaluate the quality of the consolidation process. Measurements have been made in the real dome and in a 1:1 scale model, where there is a prior knowledge about the layers' state. We have shown that valuable information may be obtained from ultrasonic analysis by the pulse/echo mode. Two complementary 2D diagrams, instantaneous power and instantaneous centroid frequency, are proposed. It has been shown that the centroid frequency can precisely estimate the depth of discontinuities, although power information seems to be better suited to locate the most affected area. This work shows promising results for the applicability of ultrasonic technology inside the restoration area of historical heritage buildings.