Great care is to be taken to preserve the historic integrity of Cleish Primary School during improvements.
The C-listed building was built as the parochial school in 1835 and is in the Cleish Conservation Area.
All existing sliding sash and case windows and later timber windows are to be refurbished, replacing existing single glazing with slim double-glazed units which will fit into the existing frame and astragal arrangement.
A few historic panes of glass remain in the building and although these will be lost, project chiefs say this will not compromise the appearance of the school.
“Windows made a substantial contribution to the character and physical integrity of most historic buildings and also to the character and interest of historic streets and places,” said the council’s development quality manager Nick Brian in a report to councillors.
“They are an important element of a building’s design and weatherproofing. Timber sash windows have a very long life if they are well made using good quality material, correctly installed and properly maintained.
“Many have been in place for at least 100 years, in some cases considerably longer, and continue to give good service. Those which are defective are often capable of repair, and this is always preferable to replacement, and frequently much less expensive.”
A condition of the work, as approved by councillors, is the new glass should be puttied into the window frames.