South Library, Islington. Photograph: Stephen McKay / Wikicommons

The Town Hall is set to save a Grade II-listed library building from disrepair, after a leaking roof left the interior of the building damaged.

Islington’s South Library, part of the Cross Street conservation area, was built around 1915.

It was designed by architect Mervyn Macartney, who as surveyor to St Paul’s Cathedral also carried out conservation works on the church, including strengthening its dome.

The Library is described as having “high architectural, historical, evidential and communal heritage values” by officers, and councillors last week gave their consent for works to protect it to begin.

Planning committee chair Cllr Angela Picknell, who is also a ward councillor where the library is located in St Mary’s, said: “It’s a lovely little building and clearly it needs protecting. I’m not biased but it needs protecting. It is one of our assets and needs to be protected for other reasons apart from that.”

The South Library is one of the old Metropolitan Borough of Islington’s Carnegie-funded libraries.

Over 2,500 buildings across the globe were funded between the 1880s and the late 1920s by Scottish-American steel magnate Andrew Carnegie, with Islington’s West and Central libraries also built on the back of donations by the philanthropist.

The building on Essex Road has, however, seen better days, with water finding its way in and inspections showing problems with slates, gutters, downpipes and leadwork.

Safe access to the main roof is not currently possible and a timber hatch from a dormer window has rotted. 

Introducing the works, a planning officer said: “The dormer will give access to a new lightweight platform. This will provide safe access to the roof to maintain the building and prevent repeated water ingress and staining to the interior spaces of the Library from previously hard to maintain sections of the roof, which is considered a public benefit.”