Fire-Tested Roof Void Closer for Compartmentation at Roof Eaves
The FIREFLY® Roof Cavity Closer is a fully certified fire-stopping solution designed to seal the gap between the roof membrane and outer tiles or sheeting at compartment lines. Constructed using FIREFLY® FB180 Ablative Batt with a factory-bonded intumescent graphite strip, the closer expands under heat to block fire spread through roof-level voids.
Ideal for both new-builds and retrofit applications, this friction-fit product installs below the membrane—eliminating the need to remove tiles or alter existing waterproofing. It’s compliant with BS EN 1363-1:2020 and helps meet Building Regulation Part B without the need for a protected 1500mm "umbrella zone."
✅ Key Features:
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Closes voids between membrane and roof tiles to maintain fire compartmentation
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Tested to BS EN 1363-1:2020 for vertical roofline installations
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Graphite intumescent expands in fire, sealing roof edge gaps
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No need to remove tiles or membranes — ideal for retrofit
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Supports compliance without a 1500mm-wide protected zone
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Suitable for installation perpendicular or parallel to the gable end
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Compatible with FB180 Batt, FIREFLY® barriers, and common wall types (brick, plasterboard, timber)
🧱 Construction & Materials:
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FIREFLY® FB180 mineral fibre ablative batt with bonded graphite strip
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Designed for vertical applications only
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White finish with dark graphite edge (visible during install)
🔧 Installation:
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Friction-fit into cavity voids
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All edges should be buttered and sealed with FIREFLY® FR Intumescent Acrylic Sealant
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Refer to FIREFLY® Drawings 017 & 018 for application guidance
📐 Product Sizes:
Stocked:
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1200 × 150 × 50mm
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600 × 150 × 50mm
Made to Order:
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1200 × 400 × 50mm
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1200 × 300 × 50mm
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600 × 400 × 50mm
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600 × 300 × 50mm
🧊 Storage:
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Store in a cool, dry area
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Do not expose to rain or frost
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Supplied bagged for transit protection