Besides the traditional repair techniques of craftsmen for masonry structures, engineering methods and procedures such as grouting and reinforcing of old masonry are available. These technical measures can help to save the monumental value of historically important buildings more effectively than the procedure of dismantling and rebuilding; and, as a rule, they are distinctly less costly. Nevertheless, too much technical aid can destroy what is meant to be preserved. For that reason the investigations described in this paper on both improvement and development of engineer-like repair techniques have been focused on the goal of minimizing interventions and modern additions as far as possible.