Hilden Mill demolition: Devastating 2021 fire blamed for needing to knock down beloved Lisburn landmark, with roof gone and walls now 'at high risk of collapse'

The much-loved Lisburn landmark was hit by arson attacks in both 2021 and 2024. Reports commissioned by site owners PJK Developments Ltd point to the first of those fires for leaving it in such a bad condition that the only thing left to do, they argue, is send in a wrecking ball.

The 19th century mill was at one point one of the largest linen-thread manufacturers in the world and played a huge part in the cultural life of Lisburn, as well as being acclaimed for the classic style of its large buildings. It closed down in 2006; despite several plans to redevelop it over the years, none have come to fruition.

Last year, PJK Developments filed an application to demolish the listed building; now, surveyors commissioned by the firm have published reports setting out their full reasons why Hilden Mill can’t be saved, and publicly laying out the severity of damage and dilapidation to the site.

The roof of one large building was completely destroyed in the June 2021 fire, says the surveyors’ report, and a buttressing wall has partially collapsed. States the report: “The loss of the stabilising effect of the roof and buttressing wall means the walls are now unstable.”

The report adds: “The remaining mill buildings scheduled for demolition also sustained extensive damage in the 2021 fire and have experienced continued dilapidation and disrepair.

“The existing mill buildings exhibit extensive fire damage and significant deterioration. Many structures are visibly roofless, partially collapsed, and overgrown with vegetation.

“The degree of structural stability varies across the site; some elevations appear relatively intact, while others are severely degraded, with exposed roof trusses collapsing inward.”

The report goes on to argue that Hilden Mill has become a serious health and safety problem, with the 2021 arson attack also raising concerns about risks to nearby housing developments.

“The roof structure of the majority of the mill buildings has been completely lost,” state surveyors. “Consequently, the walls are now unstable and are at high risk of collapse.”

Parts of two buildings can be saved, says the report, but the majority of the site is a health and safety risk to both members of the public who enter the land and nearby homes.

“Structural assessments have confirmed that the extent of the fire damage has rendered the buildings structurally unsound and in cases, retention is not viable due to significant safety risks associated with the existing structures,” conclude surveyors.

A final decision on whether to approve the demolition of Hilden Mill will be made by Lisburn and Castlereagh Council in the coming months.

Built during the 1820s and greatly expanded over the next century, the mill was listed for protection at grade B+ in 1989, but has lain empty for almost 20 years since the linen-thread factory there shut down.

Its previous owners were at one point given planning permission for up to 650 homes on the 24-acre site, but construction never began.

PJK Developments bought the mill in 2017, at the time indicating that they hoped to create an affordable housing scheme with more than 200 homes.