How Istanbul's Building Stock Ended Up Full of Duplicate Records — and Why It Now Has to Fix Them

Istanbul's land registry offices are sitting on a problem that predates the internet. Tens of thousands of property files held across the city's 39 district cadastre directorates contain duplicate or mismatched photographic records — the same building photographed multiple times under different parcel numbers, or images from one decade attached to files describing a structure from another. The problem has been building since at least the 1980s, when Turkey began digitising its tapu (title deed) archive, and it is only now, under pressure from post-2023 earthquake safety legislation, that the Tapu ve Kadastro Genel Müdürlüğü (TKGM), the General Directorate of Land Registry and Cadastre, has formally committed to a systematic audit and replacement programme.

The stakes are higher in Istanbul than almost anywhere else in Turkey. The February 2023 Kahramanmaraş earthquakes, which killed more than 50,000 people across eleven provinces, forced a reckoning with how poorly the state understood its own building stock. Istanbul sits astride the North Anatolian Fault and municipal engineers have long warned that a significant portion of the city's residential buildings, particularly in districts such as Bağcılar, Avcılar, and Zeytinburnu, were constructed before modern seismic codes came into force in 1998. If emergency responders and urban planners cannot trust the photographic record attached to a property file, they cannot quickly verify whether a building has been retrofitted, demolished, or quietly replaced by an illegal structure.

The Paper Trail That Created the Problem

The duplication issue is partly a product of Istanbul's extraordinary growth rate. The city's population expanded from roughly 2.8 million in 1970 to more than 15 million today, according to Turkish Statistical Institute (TÜİK) figures, with most of that growth driven by informal construction in what were once agricultural villages on the European and Anatolian fringes. Each time a district was absorbed into the metropolitan boundary — Sultangazi and Esenyurt were among the last major incorporations — local cadastre records were merged into the central TKGM database. That merger process, repeated dozens of times over forty years, introduced systematic image mismatches. A photograph taken for a village mukhtar's office in Pendik in 1994 might now sit inside a TKGM digital file alongside a satellite capture from 2019, both nominally representing the same parcel but showing structures twenty-five years apart.

Compounding the problem is the way Istanbul's construction sector operated during the gecekondu era. Illegal or semi-legal dwellings were periodically regularised under successive amnesty laws — most recently under Law No. 7143 in 2018 — and each regularisation wave triggered a new round of photography by teams working under time pressure and without standardised equipment. The result, according to documentation published by the Chamber of Surveying and Cadastre Engineers (HKMO), is that an estimated 20 to 25 percent of Istanbul parcel files contain at least one photographic record that cannot be reliably matched to a current physical structure.

What the Audit Means on the Ground

The TKGM audit, which began in earnest in the first quarter of 2026, is prioritising districts inside Istanbul's designated urban transformation zones first. The Fikirtepe neighbourhood in Kadıköy, one of the largest urban renewal areas in Europe by footprint, is an early test case: thousands of parcels there have changed hands or been demolished since 2013, and the photographic archive has not kept pace. Field teams equipped with tablet-based capture software are working block by block through Fikirtepe and the adjacent Dumlupınar Mahallesi, cross-referencing new images against both satellite data and the physical inspection reports required under the post-2023 Yapı Denetim amendments.

Property owners who discover their title file contains a duplicate or outdated image are not currently facing penalties, but legal advisers working in Istanbul's notary offices along Ankara Caddesi in Eminönü have noted a rise in clients seeking pre-emptive corrections before planned sales. A clean, verified photographic record is increasingly demanded by mortgage lenders following guidance issued by the Banking Regulation and Supervision Agency (BDDK) in March 2026, which tightened collateral documentation requirements for residential loans in high-seismic-risk zones.

The practical advice from cadastre specialists is straightforward: owners of older properties in Avcılar, Bağcılar, Zeytinburnu, and the Anatolian-side districts of Kartal and Maltepe should request a formal parcel inquiry at their local TKGM directorate before the end of 2026. The directorate can flag duplicate image entries and initiate a correction order at no cost to the owner. Waiting until a sale or an inheritance transfer to discover the discrepancy can delay completion by months.