A mounting rail for mounting tiles to a backing system of a building wall structure comprises a tile support linked with a back-fixing rail via a tile-support carrier. The tile-support carrier comprises an acoustic damper between the tile support and the back-fixing rail. This impedes the transmission of acoustic energy from the tiles to the backing system, and so improves the acoustic insolation while the mechanical stiffness of the tile-support carrying arm is maintained. The acoustic damper may be provided in the form of one or more angled bends, apertures, an obtusely angled connection of the tile-support carrier to the back-fixing rail or a connection of the tile-support carrier at an upper or lower end of the back-fixing rail, or combinations of two or more of these features.