L5.T1. Basic Installation Principles

Basic principles

Cavity barriers are either:
• Over-sized to create a compression fit
 • Sized to match the cavity width for a friction-only fit

For the cavity barrier to perform as intended, the installation must achieve the amount of compression shown on ARC’s product datasheet

Cavity barriers must be installed between the internal leaf and external leaf with any partial fill cavity insulation interrupted

Key guidance for the installer:

The cavity barrier must be of the correct size for the cavity width (including compression where appropriate). The barrier must fully fill the cavity from external brick to internal block.

The cavity width must be accurate. The cavity insulation should be cut back where the barrier will be located.
At the end of a run, or at a corner, lengths of barrier should be cut to the required length, and then tightly butt jointed ensuring no gaps remain. Barriers should not be bent around corners.
Excess polythene should be removed from joints.
The cavity must be clear from debris.

The appropriate compression or friction fit ensures the barrier will not be dislodged in the event of a fire.

You should not attempt to squash the barrier before installation. Although this can make the barrier easier to fit, it is likely to cause gaps and may damage the barrier, resulting in reduced performance.