Ultrasonic measurements have been implemented in past years in the Cultural Heritage F ield with the aim to improve the diagnostic process of a monument prior to any restoration. This paper presents the results of a study regarding the application of non - destructive ultrasonic techniques in evaluating the conservation state of the d olmen Sa Coveccada in northern Sardinia (Italy). In this context the use of the ultrasonic techniques integrated with minero - petrographycal and physical data as well archaeological information, was very effective both to define the elasto - mechanical properties of t he building materials such as lo ngitudinal ultrasonic velocity and fracture coefficient, and to detect the presence of discontinuities caused by alteration phenomena. In addition, the ultrasonic techniques were used in laboratory on samples of the same vo lc anic building materials of the d olmen to investigate the repairing efficiency of chemical consolidating materials such as epoxidic resins and to test their compatibility with the investigated materials.