Cavity barriers are critical passive fire protection elements designed to prevent the spread of fire and smoke through hidden cavities in buildings, particularly within walls, floors, and roofs. In the UK, their correct use is strictly governed by building regulations (notably Approved Document B).

🔥 What Are Cavity Barriers?

Cavity barriers are installed to:

• Close concealed gaps between building elements (e.g., cladding systems, walls, and floors).

• Prevent fire and smoke from using these gaps as a route to spread.

• Delay fire spread long enough for occupants to escape and the fire to be controlled.

🧱 Where Are They Used?

Cavity barriers are typically installed in:

• External wall cavities (especially in ventilated rainscreen cladding systems)

• Party walls and compartment walls

• Floor-to-wall junctions

• Roof voids and lofts

• Curtain walling and spandrel zones