Fire or sound blocking components are configured to resist the transmission of fire, heat or sound through a gap in a wall assembly. The components can be elongate and have a profile of a consistent cross-sectional shape along the length of the component. In some arrangements, the component is configured to provide fire or sound blocking to a dynamic head-of-wall joint of a wall assembly. In other arrangements, the component is configured to provide fire or sound blocking to a reveal gap within or along an edge of a wall assembly.