Roof cavities are one of the most overlooked areas in fire protection design. In buildings where compartmentation is critical—such as multi-residential units, schools, or healthcare facilities—an unprotected or poorly sealed roof void can quickly undermine an otherwise compliant fire strategy.
Fires in roof spaces are not uncommon. According to UK Home Office Fire Statistics, hundreds of fires originate in roof or loft areas every year, often spreading rapidly and unnoticed due to poor visibility and the concealed nature of the void. In multi-storey and terraced buildings, fires in roof cavities can quickly spread and bridge compartments, threatening multiple units simultaneously.
The result? Devastating property damage and increased risk to life.
That’s why cavity barriers are a requirement under Approved Document B, and in particular, barriers within roof voids must restrict fire and smoke passage for a minimum period, often 30 to 60 minutes depending on the building classification.
DESIGNED TO CONTAIN FIRE AT ROOF LEVEL
Designed for use above fire-rated partitions in pitched or flat roof systems, the Protecta FR Membrane Barrier provides a robust and tested solution for compartmentalising roof cavities. It achieves EI 60 performance and utilised test conditions to EN 1363-1 and EN 1366-4, offering reliable fire compartmentation where roof membranes pass over internal partitions.
The system combines a graphite-based intumescent membrane with a Protecta FR Board, designed to expand under heat, seal off the membrane, and prevent fire and smoke from bypassing compartment lines.
WHERE AND HOW IT WORKS
The system is compatible with:
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Flexible walls (min. 95mm, timber or steel studs with 12.5mm board each side)
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Rigid walls (min. 95mm concrete or masonry)
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Protecta FR Board Partition Walls (per ETA 23/0496)
SMART, SIMPLE INSTALLATION
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Fixing directly into roofing battens at ≤200mm centres
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Easy integration with rafters, even when spacing is tight
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Can be sealed using Protecta FR Board and FR Acrylic where needed
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Allows flexibility to protect awkward voids and corners using intuitive detailing
WHY CHOOSE PROTECTA
As with all our fire-stopping systems, the FR Membrane Barrier is backed by rigorous third-party testing, practical installation guidance, and full technical support. It reflects our mission to provide tested, trusted solutions that meet modern building challenges.
If you’re designing or retrofitting a roof system and need to ensure your partitions remain compliant, the Protecta FR Membrane Barrier is a system you can rely on. Log into the Members Hub to download the FR Membrane Barrier Technical Assessment.
For more details or technical support, contact our Technical or Sales team: technical@polyseam.com | sales@polyseam.com
Products developed and manufactured by Polyseam Ltd.
