Thousands of buildings across the country, particularly older structures, are vulnerable to serious damage in earthquakes, as they have been subject to sloppy structural modifications or inadequately maintained, top civil engineers have told Kathimerini. Experts at the National Technical University of Athens say the removal of walls and columns from old buildings without the prior approval of a civil engineer is «criminal.» «Houses have a certain balance which we upset with such interventions,» said Panayiotis Karydis, a specialist in anti-seismic structures at the university. Karydis also criticized the fact that many buildings declared unstable following earlier earthquakes have been since recharacterized as stable without the necessary repairs having been completed. Karydis, who toured parts of the Peloponnese shaken by a 6.5-magnitude quake earlier this month, said older buildings were always more vulnerable. Around a quarter of the country’s buildings – that is 1.3 million structures – were built before 1960. Many of these buildings have no anti-seismic protection, particularly if they have been modified, according to Karydis, who condemned the practice of farmers converting warehouses into homes to rent to immigrant laborers. Costas Trezos, a colleague of Karydis, said the damage wreaked on hundreds of homes in the Peloponnese «was inevitable.» «In fact, the damage was relatively little in view of the size of the quake,» Trezos said. Both experts agreed that most new structures in Greece are resistant to quake damage. But they stressed the importance of homeowners enlisting a surveyor to make any structural changes.