In 1999, a devastating earthquake struck the bay of Izmit. Its affect on construction law continues to today.
In 2004 the government passed new legislation requiring all construction after this date to meet modern earthquake proof standards.
That's not to say that all construction before this date was not earthquake proof with the vast majority of buildings unaffected by the 1999 earthquake.
This law affects many aspects of construction quality, in all sectors of construction. Since that date construction standards have accelerated in Istanbul, with Turkish firms now building in many Middle East countries. Turkish firms now build all over the world from metro lines, to bridges, to shipping terminals.
Buying through one of Turkey's big construction firms guarantees quality, and a quick view of their technical specification will prove this. Smaller firms are tightly regulated now, with even the smallest of buildings going through harsh testing to ensure safety in all aspects, not just earthquake standards. Fire safety standards are just as strict, as are testing of the elevators that are installed.
Even a complexes swimming pool comes under independent inspection standards to ensure safety of their users.
It is a testament to the efforts of the Turkish government since 2004. The governments current efforts are concentrated on urban renewal, with many city centre stock being pre 1999. This stock is currently urgently being replaced, with the government offering residents and builders incentives to replace small apartment blocks, by combining parcels of land, to create larger plots for large complexes.