The flooding took place this summer and is still the subject of debate between insurers and the installers of an under-floor heating and ventilation system.
It is understood to have caused a substantial amount of water to leak down into the ICE library making half the library inaccessible to visitors as well as damaging a large number of books and papers.
ICE head of knowledge transfer Mike Chrimes told NCE that of the 4,500 items damaged in the flood, most were dried in situ with about 600 being sent to two professional book restoration firms.
One of the techniques employed by these firms would be freeze drying whereby damaged books are first reshaped into their original form and fast frozen.
"There are only about four books which were damaged beyond repair," said Chrimes who characterised the losses as "not significant".
Chrimes told NCE that parts of the library will remain inaccessible to visitors for at least another three weeks.
It is understood that the heating and ventilation system failure has caused damage throughout the building.
"A number of other rooms were affected including the Business centre and surrounding rooms, council office, president’s office, and minor damage to the DG’s office," said an ICE spokesman.
"Since the event, we have been working to ensure that the effect on members, and on the operation of the Institution as a whole, is minimised."