Turkey Earthquake Building Codes: How to Verify Developer Construction Standards Post-2023

Why This Matters After the 2023 Earthquakes

The February 2023 Kahramanmaras earthquakes (magnitude 7.8 and 7.5) killed over 50,000 people and destroyed or severely damaged more than 300,000 buildings across southeastern Turkey. The disaster exposed widespread failures in building code enforcement, construction quality, and regulatory oversight that had accumulated over decades of rapid urbanization.

For foreign property buyers, construction quality verification is no longer optional. It is the primary due diligence task.

Turkey's Earthquake Building Code: TBDY 2018

The current earthquake building regulation, TBDY 2018 (Turkiye Bina Deprem Yonetmeligi), came into force on January 1, 2019, replacing the 2007 code. It was published in the Official Gazette on March 18, 2018 and is available at https://www.resmigazete.gov.tr/eskiler/2018/03/20180318M1-2.htm.

Key requirements under TBDY 2018 include updated seismic hazard maps based on probabilistic seismic hazard analysis (PSHA) rather than older deterministic maps, mandatory site-specific geotechnical investigation for all new construction, minimum C25/30 concrete strength for most structural elements (many older buildings used C16 or even lower), stricter column and beam dimension requirements, enhanced shear wall requirements especially for taller buildings, and more conservative design coefficients for high-seismicity zones.

The updated seismic hazard maps are maintained by AFAD (Disaster and Emergency Management Authority) and are publicly accessible at https://tdth.afad.gov.tr. You can enter any address and see its seismic design parameters.

The Building Inspection System

Under Law No. 4708 (Building Inspection Law), developers of most new buildings must engage a licensed building inspection firm (yapi denetim kurulusu). These firms are responsible for verifying that construction matches the approved structural project, that materials meet specified standards (concrete, reinforcement steel, etc.), and that workmanship is adequate at each construction stage.

The building inspection firm conducts inspections at the following stages: excavation and foundation, column and beam reinforcement placement (before concrete is poured), each concrete pour, structural framing completion, and final inspection before iskan.

The Ministry of Environment, Urbanization and Climate Change maintains a Building Inspection Information System (Yapi Denetim Bilgi Sistemi) at https://yds.csb.gov.tr where you can check whether a building has an assigned inspection firm and the status of its inspections.

How to Verify a Specific Property

Check 1: Building Permit Date

The building permit (yapi ruhsati) date determines which code the building was designed to. Post-January 2019 means TBDY 2018 applies. Between 2007 and 2018 means the 2007 code applied, which was weaker but still reasonable. Before 2007 means significantly lower standards. Before 2000 means the 1975 or 1998 code applied, with substantially lower requirements.

Request the yapi ruhsati from the developer or the local municipality's construction department (imar mudurlugu). This is a public document.

A yapi ruhsati is valid for five years. If construction ran past that without a formal extension, the permit lapsed and the legal basis for the build is open to question, so check the issue date against the actual construction timeline.

Check 2: Geotechnical Report

TBDY 2018 requires a site-specific geotechnical report (zemin etudi) for all new construction. This report characterizes the soil conditions and determines the seismic design category. Request this from the developer. It should include borehole data showing soil layers and properties, the soil class (ZA through ZF under TBDY 2018), liquefaction risk assessment for relevant soil types, and recommended foundation type.

If the developer cannot produce this report, the building may not have been designed with proper site-specific seismic data.

Check 3: Structural Project

Every building must have an approved structural project (statik proje) prepared by a licensed structural engineer. Request a copy and have an independent engineer review it, particularly checking the concrete grade specified (should be C25/30 or higher for TBDY 2018 buildings), reinforcement detailing at column-beam joints, shear wall adequacy for the building height and seismic zone, and foundation design relative to the geotechnical report.

Verify the engineer, not only the drawing. The structural engineer must be registered with the Chamber of Civil Engineers (IMO), which since 2023 has pursued disciplinary proceedings against engineers linked to collapsed buildings, and registration and disciplinary status can be checked with the chamber. For a new build, also request the concrete compressive strength test reports from a TURKAK-accredited laboratory, continuous across the pour schedule rather than a single sample. TBDY 2018 sets C25/30 as the floor for most residential structures, with C30/37 or higher for taller buildings and the highest-hazard locations.

Check 4: Building Inspection Records

For buildings subject to Law No. 4708, check the inspection firm's records through the Ministry's system. Verify that all required inspections were completed and that no significant non-conformances were recorded.

Check 5: Iskan (Habitation Permit)

The iskan belgesi confirms the building passed final inspection and complies with the approved project. A building without iskan may have unresolved code compliance issues. Some buildings in Turkey have been occupied for years without iskan, which is technically illegal but common.

Law No. 3194, the Zoning Law, is what gives the iskan its teeth. Without it a building cannot legally be occupied, connected to permanent utilities, or have individual unit title deeds (TAPU) issued. A developer handing over units before iskan is asking you to accept a unit that cannot yet be titled in your name.

Check 6: Independent Structural Assessment

For existing buildings, especially those built before 2019, commission an independent structural engineer to assess the building. This typically costs $1,000-3,000 USD and includes visual inspection of structural elements for cracking, spalling, or exposed reinforcement; concrete core sampling and compressive strength testing; reinforcement scanning using ground-penetrating radar or similar technology; and comparison of the as-built structure with current code requirements.

Red Flags

Watch for visible concrete defects (honeycomb patterns, segregation, excessive cracking), exposed or corroded reinforcement, soft story configurations where the ground floor has significantly less stiffness than upper floors (common in buildings with open ground-floor parking), and buildings where the developer cannot or will not produce structural documentation.

The soft story (yumusak kat) problem was a leading cause of collapse in the 2023 earthquakes. Under TBDY 2018, strict requirements address this vulnerability, but many older buildings remain at risk.

Post-2023 Enforcement Changes

Following the earthquakes, the government implemented increased penalties for building inspection firms under amended Law No. 4708, criminal prosecutions of developers and inspectors involved in collapsed buildings, expanded urban transformation requirements under Law No. 6306, and mandatory retrofit assessments for certain building categories in high-seismicity zones.

Two of those reforms change what you should ask for. Inspection firms are no longer selected and paid by the developer in the old way: the Ministry assigns them under a rotation system being phased in, with earthquake Zone 1 and Zone 2 provinces first, which removes the conflict of interest that shaped the previous system. Penalties under amendments to the Turkish Penal Code now reach up to 22 years of imprisonment for developers, engineers and inspectors held responsible for violations that cause structural failure. The Ministry also publishes lists of suspended and delisted inspection firms, expanded sharply after 2023, so check the firm assigned to your building against them.

Earthquake Insurance (DASK)

Compulsory earthquake insurance through DASK (Dogal Afet Sigortalari Kurumu) is mandatory for residential property and is required for TAPU registration, utility connections and mortgage applications. Premiums vary by location, construction type and building age, and coverage is capped at roughly 1.2 million TL. DASK covers structural earthquake damage only, not contents, alternative accommodation, or fire following an earthquake, which is why most foreign buyers add supplementary private earthquake cover (ek deprem sigortasi) through a Turkish insurer.

For updated construction quality verification guidance in Turkey, Bektu provides detailed checklists at https://bektu.com.

Sources

- TBDY 2018: https://www.resmigazete.gov.tr/eskiler/2018/03/20180318M1-2.htm

- Building Inspection Law No. 4708: https://www.mevzuat.gov.tr/MevzuatMetin/1.5.4708.pdf

- AFAD Seismic Hazard Maps: https://tdth.afad.gov.tr

- Building Inspection Info System: https://yds.csb.gov.tr

- Law No. 6306 Urban Transformation: https://www.mevzuat.gov.tr/MevzuatMetin/1.5.6306.pdf