Cavity barriers should be installed near the edges of internal cavities, such as window and door openings or extract vents. They should also be placed at junctions whenever the wall cavity is aligned with a building compartment wall or floor. There are some exceptions to this requirement, depending on how fire-resistant the building material is. Cavity walls of a particular material or thickness may not require additional cavity barriers placed at junctions.
Before installing cavity barriers, it’s essential to consider building movements and deformations where the barriers are placed. Settlement, sway, thermal expansion, and penetrations by deformations can negatively affect the efficacy of a cavity barrier.