A probe into dry rot at Towneley Hall has revealed extensive damage to several rooms, which will cost Burnley Council thousands of pounds to repair.
The dry rot infestation at the historic Grade I listed building must now be tackled by specialist workmen, with the council setting aside an initial £56,000 for the work.
The dry rot has caused severe damage to a gallery, landing and taxidermy area on the second and third floors.
A Burnley Council spokesman said: “Towneley Hall is a historic building and like all old buildings, it requires maintenance and repair.
“The council has taken expert advice and set money aside in this year’s capital programme towards the cost of the repair work.
“Given the historic nature of this Grade I listed building we will be using specialist contractors who are experienced in the restoration of ancient buildings.”
A report from Robinsons Preservation Ltd, which inspected the hall in February, said that urgent action was now required.
Five rooms on the second and third floors require extensive repairs to prevent further water damage to the building.
Towneley Hall was constructed in around 1400 and completed in its quadrangle form around a century later.
The original building layout has been altered throughout various centuries including the north west wing in circa 1626 and later widened by additions to the outer side around 1737.
The property was owned and occupied by the Towneley family for more than 500 years. In 1901 one of the daughters, Lady O’Hagan, sold the house to Burnley Corporation. The family departed in March 1902.
Today the building is used as a museum and art gallery.