Designed to block fire and smoke, the ARC Cavity Stop Sock Fire Barrier fits securely in external masonry wall cavities. Suitable for vertical or horizontal use, it meets the requirements of Approved Document B.  With a fire rating of up to 4 hours and built from non-combustible rockfibre mineral wool, this barrier enhances building safety. Its 1200mm length ensures wide coverage, helping to close cavities at eaves level and contain fire spread within the cavity space.

Key Features

Length: 1200mm

Insulation: Non-combustible rockfibre mineral wool

Thermal conductivity: 0.037W/mK

Fire Rating : 4hrs with EN1366-4 of Test standard

Orientation : Suitable for vertical or horizontal cavities

Datasheet

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ARC

ARC Cavity Stop Sock Fire Barrier

£104.00
Fire-resistant cavity barrier made from rockfibre mineral wool. Suitable for vertical and horizontal use in masonry walls. Rated up to 4 hours fire resistance with low thermal conductivity.

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Designed to block fire and smoke, the ARC Cavity Stop Sock Fire Barrier fits securely in external masonry wall cavities. Suitable for vertical or horizontal use, it meets the requirements of Approved Document B.  With a fire rating of up to 4 hours and built from non-combustible rockfibre mineral wool, this barrier enhances building safety. Its 1200mm length ensures wide coverage, helping to close cavities at eaves level and contain fire spread within the cavity space.

Key Features

Length: 1200mm

Insulation: Non-combustible rockfibre mineral wool

Thermal conductivity: 0.037W/mK

Fire Rating : 4hrs with EN1366-4 of Test standard

Orientation : Suitable for vertical or horizontal cavities

Datasheet

Description

Designed to block fire and smoke, the ARC Cavity Stop Sock Fire Barrier fits securely in external masonry wall cavities. Suitable for vertical or horizontal use, it meets the requirements of Approved Document B.  With a fire rating of up to 4 hours and built from non-combustible rockfibre mineral wool, this barrier enhances building safety. Its 1200mm length ensures wide coverage, helping to close cavities at eaves level and contain fire spread within the cavity space.

Key Features

Length: 1200mm

Insulation: Non-combustible rockfibre mineral wool

Thermal conductivity: 0.037W/mK

Fire Rating : 4hrs with EN1366-4 of Test standard

Orientation : Suitable for vertical or horizontal cavities

Datasheet

Payment & Security

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Trusted Protection in Wall Cavities

The ARC Cavity Stop Sock is made for use in external masonry wall cavities, helping prevent fire and smoke from spreading. It’s especially suited to buildings where cavity barriers are required by regulation.
Each 1200mm barrier can be installed either vertically or horizontally, giving flexibility across building designs. The product helps meet building control standards and fits securely into the cavity without fuss.

4-Hour Fire Rating You Can Rely On

Tested to EN1366-4 standards, the ARC Cavity Stop Sock holds a fire resistance rating of up to 4 hours. That’s added time for safe evacuation and damage control.

Non-Combustible Mineral Wool Core

The core of the product is made from dense rockfibre mineral wool. It resists high temperatures without melting, thereby helping to maintain its structure under intense heat.

Insulates While Protecting

Beyond fire safety, the barrier offers a thermal conductivity of 0.037W/mK. This supports energy efficiency by reducing heat loss through wall cavities.

Built to Comply with Approved Document B

Specifically recommended in Approved Document B, this cavity stop sock is a trusted choice for specifiers and contractors. It helps close cavities at roof level and around windows, making sure your build stays compliant.

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ARC Cavity Stop Sock Fire Barrier - Armstrong Cheshire
ARC

ARC Cavity Stop Sock Fire Barrier

From £104.00

Designed to block fire and smoke, the ARC Cavity Stop Sock Fire Barrier fits securely in external masonry wall cavities. Suitable for vertical or horizontal use, it meets the requirements of Approved Document B.  With a fire rating of up to 4 hours and built from non-combustible rockfibre mineral wool, this barrier enhances building safety. Its 1200mm length ensures wide coverage, helping to close cavities at eaves level and contain fire spread within the cavity space.

Key Features

Length: 1200mm

Insulation: Non-combustible rockfibre mineral wool

Thermal conductivity: 0.037W/mK

Fire Rating : 4hrs with EN1366-4 of Test standard

Orientation : Suitable for vertical or horizontal cavities

Datasheet

Size/Pack

  • 100mm Cavity 120 x 100 x 1200mm (20/pack)
  • 125mm Cavity 135 x 120 x 1200mm (15/pack)
  • 150mm Cavity 160 x 120 x 1200mm (15/pack)
  • 200mm Cavity 210 x 150 x 1200mm (8/pack)
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