The client, the main catering supplier Turkish Airlines flights, requested a seismic retrofit for their production and headquarters building in Istanbul. The building consisted of six reinforced concrete blocks constructed in the 1970’s, and therefore it did not comply to seismic requirements. The scope of services included a seismic performance evaluation resulting in three alternative retrofitting proposals for the application of; (1) seismic base isolation at basement level, (2) buckling restrained braces (BRB’s) and (3) steel plate shear walls (SPSW) to be added to various floors to provide additional stiffness and dissipate energy by damping. Construction cost, applicable schedule and business interruption durations were determined for each alternative in addition to post-earthquake performance in terms of business sustainability. The services also included providing a site specific Seismic Hazard Analysis (SHA) report as well as a retrofitting design against punching risk by means of replacing steel brackets at the top of the columns in addition to tender documents, assistance in contractor selection, project and construction management at site.