Cavity Fire Barriers

Cavity fire barriers are an essential fire protection measure for your external walls.

Cavity fire barriers are non-combustible blocks which sit in enclosed spaces in external walls. These spaces are often designed for the ventilation and energy efficiency of a building, however, cavities also act as a passage, or chimney, for fire. A cavity wall will transfer flames, smoke and hot gases throughout a building if there are no measures taken to prevent the spread. This is why cavity fire barriers are designed to sit within external wall cavities and expand when exposed to fire, blocking the cavity to slow and limit the spread of fire.

This measure is now mandatory according to the latest regulations, meaning new buildings will have to be constructed with cavity fire barriers in place, and older buildings must undergo a Fire Risk Assessment for rectification measures.

Oakleigh Contracts specialises in rectification projects, and are able to provide full consultation, design, and installation of cavity fire barriers for your building.

We work with independent fire engineers, who can carry out a Fire Risk Assessment and further verify the correct products for your application.


Oakleigh Contracts partner with Tenmat and Siderise for the provision of cavity fire barriers, suitable for all types of facades. Our cavity fire barriers are tried and tested, with a range of barriers available, including ventilated fire barriers to maintain ventilation.

Oakleigh Contracts record all works on the Bolster Systems App, ensuring our clients can track the progress of their project.

Where are cavity fire barriers required?

Cavity fire barriers are required at the juncture of exterior wall cavities and compartment floors and walls. This enables the compartmentation of the exterior of a building to help contain a fire.

Cavity fire barriers are also required within internal cavities; for more about the compartmentation of internal cavities, see our compartmentation service.

Why are cavity fire barriers required?

Cavity fire barriers are a requirement for both buildings under 18 metres and high rise buildings over 18 metres because of their essential role in limiting the damage of fire. By slowing and limiting the spread of fire, cavity fire barriers give residents more time to evacuate, as well as giving firefighters more time to get inside and around the building if necessary. They increase the chances of a fire being put out, and limit the damage a fire can do to a building.

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