Skip to main content

The Fire Safety Event

8 - 10 APRIL 2025

NEC, Birmingham

Exhibitor Products

Fire extinguishers

20 Mar 2024

Roof Cavity Closer

FIREFLY Stand: 5/B110

Providing a fire-tested solution to close the void between roof membrane and tile at compartment lines, FIREFLY® Roof Cavity Closer is a specially manufactured combination of Ablative Batt & Intumescent Graphite.

The FIREFLY® Roof Cavity Closer is designed to extend the compartmentation line all the way through the roof membrane to the outer tile/sheet.

It is installed below the membrane and features a bonded intumescent graphite strip that will expand to fill the void to the outer tiles in the event of a fire.

FIREFLY® Roof Cavity Closer can be used when installing a FIREFLY® Barrier or a FB180 Batt system, in order to provide a tested and certified solution.

Manufactured using FIREFLY® FB180 Ablative Batt and an intumescent graphite layer bonded to the narrow edge of the Batt. Supplied in cut sizes suitable for intended applications, but can be further trimmed to size on site.

The FIREFLY® Roof Cavity Closer should be friction-fitted into the void and edges “buttered” and sealed with FIREFLY® FR Intumescent Acrylic. Consult drawings on the FIREFLY® website for full installation detail for various scenarios


  • Provides a practical fire-stopping solution to meet the requirements of Building Regulation Part B to close the void between roof membrane and outer tiles
  • Extends compartment fully to the exterior skin of the building
  • FIREFLY® Roof Cavity Closer achieves compliance without the need to provide a 1500mm wide protected zone (or “umbrella zone”) either side of the compartment line
  • Sits below the membrane, so no need to remove tiles or cut membrane to
    fit – perfect for retrofit
  • Can be used in conjunction with various materials within the compartment wall; including FIREFLY® flexible fire barriers, FIREFLY® FB180 Ablative Batt, timber, plasterboard and block/brickwork
  • Suitable for use both perpendicular and parallel to the gable end
  • Tested to the requirements of BS EN 1363-1:2020 and provides a tested & certified solution as part of a FIREFLY® system

FIREFLY® Roof Cavity Closer

Mineral fibre ablative batt with bonded graphite strip for use with FIREFLY® systems

Tested as a system against the requirements of BS EN 1363-1:2020

Fully tested with 3rd party certification under application

Vertical use only

Layered mineral fibre, ablative coating on both sides, white appearance with intumescent graphite strip

1200 x 150 x 50mm, 600 x 150 x 50mm (stocked) 1200 x 400 x 50mm, 1200 x 300 x 50mm, 600 x 400 x 50mm, 600 x 300 x 50mm (made to order)

Supplied bagged to provide protection in transit and on site. Do not allow the batt to be exposed to rain
Storage: cool, dry place – protect from frost


  • Passive Fire Prevention
  • Training Provider
View all Exhibitor Products

The Safety & Security Event Series