The Alexander Heritage and Research Library's move back to Queen's Park has begun with the revamp of the building - including earthquake strengthening - complete.
Its temporary location on Ridgeway St closed on Friday and the library is expected to be open in a month.
An opening has been planned for September 12.
Councillors took a tour of the revamped Alexander Heritage and Research Library last week and were impressed by what they saw.
Project manager Rick Grobecker said the refurbished building now met 67 per cent of the building code, up from the mid 20s.
It needed to meet a minimum of 33 per cent.
The Whanganui District Council had budgeted $1.03million for the upgrade but it came in at $910,000.
The Lottery WWI Commemorations, Environment and Heritage fund provided $120,117 towards a new climate control system in the collection store and mobile shelving.
Mr Grobecker said in the event of an earthquake, falling bricks would have been the biggest danger so the building's two brick skins were joined together using stainless steel bolts while the outside was replastered with fibre mesh and waterproofing.
A repaint has restored what was a cracked and flaking exterior to the exact original colour.
The wall between the centre and right wing of the building has been removed while climate control will be installed in the archives room.
New rimu door framing has been put in the rear of the building to match existing woodwork and an accessibility ramp has improved access to the front of the building.
The ends of the steel bolts on the outside of the building are the only visible marker of the refurbishment.
"(Architect Bruce Dickson) didn't want to hide the fact that it had been strengthened," Mr Grobecker said.
DML Construction were the main contractor for the revamp.