Knauf Coreboard (GB-WRTX) are gypsum wallboards developed specifically to be used in conjunction with Knauf Shaftwall System where access from one side is restricted, giving a high fire & moisture performance whilst being simple to construct. Field of Application: Knauf Coreboards are used as liner boards facing the shaft of Knauf’s Fire Rated Shaftwall systems Note: Fire resistant gypsum boards are just part of a complete fire rated assembly. To achieve a certain fire rating on a Knauf drywall assembly, the complete system components have to be installed according to Knauf’s installation guidelines.