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.
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A rather wet and windy evening, with rain in the north and showers elsewhere.
The 19-year-old's body was discovered in Builth Wells last month, just days after he was reported missing at the Royal Welsh Show.
The funeral has taken place of a one-year-old girl who died when a parked car rolled into a wall, which then collapsed on her.