Indonesia and Türkiye share a defining feature that shapes how real estate and construction decisions get made: both sit on active seismic fault systems. For Indonesian investors and developers evaluating Turkish real estate or construction partnerships, this shared geological reality is an advantage rather than a complication. It means the regulatory logic will feel familiar, even where the specific codes differ.
The regulatory framework since 2023
Following the February 2023 earthquakes in southeastern Türkiye, the country accelerated enforcement of its Turkish Building Earthquake Code (TBDY 2018), which had already tightened structural requirements considerably from earlier decades. The practical effect for investors is twofold. First, structural design now requires higher-grade concrete specifications, denser reinforcement detailing, and soil-specific foundation engineering tied to local ground surveys. Second, municipalities have increased scrutiny of as-built inspections against approved drawings, closing gaps that previously allowed developers to deviate from permitted designs during construction.
For Indonesian investors accustomed to Indonesia's own SNI 1726 seismic standards and post-Palu, post-Lombok regulatory tightening, this trajectory should read as recognizable. Türkiye's code evolution parallels what Indonesia has pursued in its own high-risk zones, and the underlying engineering principles, capacity design, ductility detailing, soil-structure interaction, translate directly between the two contexts.
Regional variation : Not all of Türkiye carries equal seismic weight in underwriting terms. Istanbul, much of the Marmara region, and the Aegean coast sit in higher seismic zones per the national hazard map, while parts of central Anatolia carry materially lower classifications. This affects both construction cost and insurance premiums, and it should factor into site selection as much as price per square metre does.
What this means for due diligence
An Indonesian investor evaluating a Turkish property or construction partnership should treat seismic compliance as a documentation exercise, not an assumption. Key items to request before committing capital include the building's structural engineering report referencing TBDY 2018 compliance, the soil survey (zemin etüdü) underlying the foundation design, and the municipal iskan (occupancy permit) confirming as-built inspection sign-off. For pre-construction or off-plan projects, the equivalent is the approved structural project file held by the municipality, which can be verified independently of the developer's own representations.
Cost implications : Post-2023 seismic compliance has added measurably to structural costs on new builds, particularly in higher zones, through increased steel reinforcement ratios and stricter concrete quality testing. Investors comparing headline construction costs across projects should confirm whether quoted figures already reflect current code requirements or an older cost basis, since the gap can materially affect budget accuracy.
Retrofit and older stock
A separate consideration applies to existing buildings, particularly in Istanbul, where a large share of the housing stock predates the strengthened code. Türkiye's urban transformation (kentsel dönüşüm) program has targeted this stock for demolition and rebuild, and Indonesian investors considering acquisition of older properties, whether for redevelopment or income, should factor in the likelihood of eventual retrofit or transformation requirements, along with the incentives and timelines that apply under that program.
Practical takeaway
Seismic regulation in Türkiye is not a niche technical footnote, it is a core underwriting variable that affects cost, timeline, insurance, and long-term asset value. Indonesian investors who bring their own domestic experience with seismic-zone real estate are well positioned to evaluate Turkish opportunities rigorously, provided they insist on the same documentation discipline they would expect at home: verified structural reports, independent soil data, and confirmed occupancy permits before capital changes hands. Working with advisors who can validate this documentation against municipal records, rather than relying solely on developer disclosures, remains the most reliable way to manage this risk.