Rehabilitation of city centres and of buildings of architectural interest is an increasing activity in Civil Engineering works. A thorough, economic and careful project demands à priori information about the original construction materials and techniques, changes to the original structure, infrastructures (water, electricity, sewage, etc) defects and foundations. Direct physical intervention on the buildings is not advisable and, therefore, non intrusive and non destructive techniques must be used. Herein it is proposed to give an account, using selected data, from a larger on going GPR survey in the study and characterization of an Art Deco building (from early XXth century). Data were collected with shielded antennas and are discussed both in 2D and 3D and, finally, the benefits of the survey are appraised confirming the potential of GPR in the investigation to support conservation interventions.