Work to replace the roof of Lancaster’s city museum will take up to eight months to complete.
The work is due to take place over the autumn and winter as part of Lancaster City Council’s programme of works to preserve some of its oldest and finest public buildings.
Scaffolding is due to be erected around the entire building from Tuesday October 3.
The works will mean that a number of stalls at the city’s Wednesday and Saturday Charter Market will move from their usual pitches adjacent to the City Museum in Market Square.
But a council spokeswoman said shoppers will be signposted to new temporary locations further down Market Street.
The work is due to be completed by May 2018.
Normal access to Lancaster Library will remain unaffected by the works and will be via a tunnelled entrance within the scaffolding framework.
The City Museum which is owned by Lancaster City Council and managed by Lancashire County Council Museum Service, will remain open to visitors as normal via the front door throughout the duration of the works.
“Disabled access to the City Museum being via the New Street entrance at the rear of the building.
Coun James Leyshon, Cabinet member with responsibility property services, said: “As custodians of this magnificent Georgian building found in the very heart of historic city of Lancaster, these works are necessary to ensure people can continue to enjoy discovering Lancaster’s past at the City Museum as well as the events, activities and wonderful collections and exhibitions on offer all year round.”