Carlisle Station, also known as Carlisle Citadel, is a Grade II listed building, built in 1847. The station had a glass roof, but over the decades it had aged and deteriorated into a fragile condition. This posed the risk of glass falling onto the public and station operational areas below. The repair of the roof was categorised as emergency works.The preservation of the building required a sensitive solution that would restore the Station as close to the original design as possible, while continuously functioning as a major transport link for generations to come. Part of that solution was to reduce the forces imposed on the original structure by the heavy glass roof by replacing it with a lightweight Texlon® ETFE system.The new Texlon® ETFE roof and facade systemThe 10,500 m2 single-layer Texlon® EFTE foil system installed at Carlisle Citadel Station is formed of 10 metre by 5 metre extruded ETFE sheets. Each has a thickness of just 250 microns.Each ETFE sheet is welded along its perimeter to form an edge that can be folded over a ‘Keder’ extrusion rod. The perimeter assembly enables a structural connection between the ETFE panel and the aluminium perimeter framing.For the facade element of the building, vertical mullions spaced along the ETFE panels have concave surfaces onto which convex mullion caps are clamped, sandwiching the ETFE foil perimeter edge into place and thus further tensioning it.