Arwel Jones, Director of Public Services at the National Library of Wales, told ITV News "our concern now is for the collection", and that it will take time for the extent of any damage to be estimated.
More top news
A chilly night with winter showers in the west and widespread frost and ice in places.
The former Siop Y Werin faces demolition as part of council plans to regenerate the town centre.
Leighton Andrews has wrritten to Carwyn Jones saying he has misled the National Assembly 'several times' since the death of Carl Sargeant.