TEHRAN -- The roof of the Si-o-Se Pol historical building will be comprehensively and fundamentally restored after 10 years, the person in charge of monitoring historical bridges in Isfahan said Wednesday. 
Hadi Allahiari said the first stage of the restoration of the roof on the east side of the bridge has started under the supervision of the technical office of the General Directorate of Cultural Heritage of Isfahan Province, and it includes styling, repairing gutters and brick pavements.
The roof of the bridge was comprehensively restored no less than a decade ago, he said, adding in recent years, case restorations had been carried out on the landmark. 
“Brick wear and interventions from the past years, especially when the bridge was a vehicle traffic route, are among the reasons for the need for comprehensive restoration of the Si-o-Se Pol bridge,” Allahiari said.
He said the roof of the bridge needs at least two stages of restoration, after which its body and doors should also be repaired in the next step.
The monitoring of bridge and case repairs are done regularly, according to Allahiari.
He said defacing and engraving and breaking the doors of the lower floor of the landmark is one of the threats to the bridge. 
Si-o-Se Pol is the largest of the eleven historical bridges on the Zayanderud, the largest river of the Iranian Plateau, in Isfahan. The bridge was built in the early 17th century to serve as both a bridge and a dam.
It is a vaulted arch bridge consisting of two superimposed rows of 33 arches, from whence its popular name of Si-o-se-pol comes, and is made of stone.