When Lady O'Hagan inherited Towneley in 1887, the Burnley Express reported that Towneley Hall had undergone a complete repair for her reception but when Burnley Corporation took over in 1902 the Borough Surveyor reported the building was in a bad state of repair.
The first work in 1902 was pointing the walls and overhauling the lead-work on the roof. Central heating was installed and the South wing roof was modified to light the Long Gallery from above. There is no evidence of any regular maintenance over the next 25 years but the North wing roof was kept in good condition first when the art gallery was completed in 1908 and later when a second gallery was created to display watercolour paintings in 1923.
The next major repair work was the pointing of the North wing stonework in 1928.This continued into 1929 with the pointing of the sides of the chapel and repairing the Towers. Further work in 1930 and 1931 saw slate repairs, lead gutters relaid and painting all the windows outside. The purpose of the pointing was to make the building less damp but by the 1920s concrete rather than lime mortar was normally used and this actually stopped the walls from drying out.
While changes were made to the North wing, the South wing was deteriorating. In 1933, dry rot was found above the Long Gallery and work began on the South wing roof. The Borough Surveyor also reported that the ivy growing on the walls was causing damage to the plaster on the inside of the walls, however it was 1962 before the dead ivy was stripped down from the North wing and the walls replanted with Virginia creeper. In January 1938 it was reported that the Long Gallery ceiling was in a dangerous condition. Work began immediately on the ceiling and in the autumn of 1938 further slating work work was done on the South wing and above the Entrance Hall.
At the start of the war in September 1939, sandbags were put up around the ground floor windows but by July 1940 the sandbags were collapsing and growing fungus and the sandbags were removed. The war did not stop emergency repairs when in 1943 joiners renewed beams in the chapel roof and the slaters and plumbers made the chapel roof weatherproof.
Dry rot was found in the ground floor of the South wing in 1951 and in 1952 the Borough Surveyor made a detailed survey of the building to ensure it was free from dry rot. At that time defects were found in the lead guttering above the Long Gallery and repaired immediately. The Borough Surveyor's report has not survived but the Curator's report for 1954-55 details dry rot not only in the South wing but also in the floors on the ground floor and first floor of the North wing. It was at this time that two wooden pillars were placed in the Servants' Hall to support the floor above.
The next emergency occurred in 1960 when immediate repairs were required to the main joist supporting the Chapel floor and in 1962 there was a further discovery of dry-rot affecting a doorway, joists and floorboards. After rot was discovered over one of the windows in the entrance hall in March 1968, it was decided to examine the remainder of the timbers above the entrance hall and the centre of the ceiling was found to be sagging. This required a thorough clear-out of the roofspace by a firm of industrial cleaners and it took a further two years before the repairs to the ceiling were completed in July 1970.
By 1983 it was recognised that the concrete strap pointing that had taken place over the past 50 years was damaging the building and work began on replacing all the strap pointing with flush pointing. Dry rot stops when the water content of the wood is reduced to below 20%, so it was essential to make the roof watertight and a program of work on the roof was established for reslating and the renewal of the gutters, beginning with the South wing. This work continued throughout the 1980s, moving on to the North wing with re-roofing of the Watercolour Gallery, which was completed in 1994.