Erbil citadel is a World Heritage site located on top of a 30m height artificial mound and its human settlement is thought to be over 8,000 years old. Erbil Citadel is an imposing example of a multilayered archaeological mound still physically emerging from the surrounding landscape. The physical structure of the Citadel town is characterized by the permanence of the Ottoman period urban form and street pattern on top of the mound.

The executed project is centered around 8 groups of buildings and involves a long series of studies and thorough research from different disciplines, the main ones being: geometric survey of existing buildings, historical research, architectural analysis of historical and construction phases and geotechnical and structural assessment studies. In light of these studies, a preservation/restoration project, together with an operations manual was drafted.

One of the most important aspects, which generated a great discussion, was defining the appearance and physiognomy to be recovered for each building, i.e. determining the historical and construction phase for each case. To achieve this, an architectural analysis assessing the remains of the original architecture was carried out. This gave us an insight into the development of buildings through the ages and allowed us to better understand which the original structure is and why. Eventually, we were able to know the dimensions and distribution of the parts missing.

Characterization of diverse materials present in the citadel buildings was a tough process too. Materials composing the buildings were numerous and varied in condition and state. Their heritage significance and peculiarities of many of them -traditional construction materials of different quality- made it necessary to conduct a specific characterization campaign of mechanical and durable features, allowing for the definition of the material state and existing damages, processes diagnose and prescription of relevant corrective measures in alignment with materials behavior and construction typology.