Plans to change the front of the Forum have been approved
Planners have agreed to the re-modelling of the Forum building in Norwich, home to the main Norfolk county library.
The Forum Trust has been given planning permission to enclose an open area at the front of the building.
Hopkins Architects, which designed the building, has given its broad support to the plans.
But the Norwich Society condemned the plan as "piecemeal development of a landmark building in the city".
The Forum, designed by Sir Michael Hopkins, replaced the old library which was destroyed by fire in 1994.
About 100,000 books were lost in the blaze, although many ancient documents were rescued.
Hopkins Architects said when the building was designed it was meant to be asymmetrical and also to be able to be used in a flexible way.
The Norwich Society questioned the benefit of the scheme and said the group expected the building to soon be listed.