Abstract: A device to brace a door frame (3), to prevent the sides of the door frame buckling when grout or other filler material is used to fill a gap between the door frame and an adjacent wall comprises, a pair of elongate support member (17), for contacting the sides of the door frame (3), upper and lower means (25, 27) coupling the support members together for movement between a retracted position and an expanded position, and means for selectively locking the support members (17) is the expanded position with the support members contacting and bracing the sides of the door frame (3).