Cavity Stop Socks for Cavity Wall Fire Protection
Cavity stop socks are a key component of passive fire protection, designed to help restrict the spread of fire and smoke within concealed wall cavities. Commonly used in residential and commercial construction, they provide an effective way to seal cavities and support fire compartmentation within buildings.
This collection sits within our wider Cavity Closers & Cavity Wall Insulation range and includes options for standard cavity walls, party walls, and projects requiring enhanced fire performance. With multiple sizes available, these solutions are designed to integrate easily into both new-build and refurbishment work.
Cavity fire socks form part of a broader passive fire protection strategy and should be selected and installed in line with UK Building Regulations (Approved Document B) and the specific fire strategy for the building. Fire performance varies by product and application and must always be confirmed against the manufacturer’s test data and certification.
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What Are Cavity Stop Socks?
Cavity stop socks are compressible fire-resistant barriers installed within cavity walls. Once positioned, they expand to fill the cavity, limiting airflow and reducing the risk of fire and smoke travelling unseen through wall voids.
They are typically installed in:
- Masonry cavity walls
- Timber frame constructions
- External wall cavities
- Separating and compartment walls
By sealing these concealed spaces, cavity stop socks contribute to a building’s overall fire safety strategy and help meet regulatory requirements.
Types of Cavity Fire Socks
Different building layouts and fire protection strategies require different cavity fire stopping solutions. This range covers the most common applications found on site.
Standard Cavity Stop Socks
Standard cavity stop socks are suitable for general cavity wall applications where fire and smoke resistance is required. They are commonly used to form continuous barriers within external and internal wall cavities.
Typical applications include:
- External cavity walls
- Internal wall junctions
- General fire stopping in residential and commercial buildings
They offer a practical balance of performance, ease of installation, and reliability.
Party Wall Cavity Stop Socks
Party wall cavity stop socks are designed to seal the cavity between adjoining properties. In residential developments, they play an important role in preventing fire and smoke from spreading between neighbouring dwellings.
They are commonly used in:
- Terraced housing
- Semi-detached properties
- Apartments and multi-occupancy buildings
Correct installation helps maintain fire separation and supports compartmentation requirements.
Higher Performance Cavity Stop Socks
Higher performance cavity stop socks are intended for use where increased fire resistance requirements apply. These are often specified in projects with more demanding fire strategies or additional regulatory considerations.
Fire resistance periods and classifications are product-specific and depend on the tested configuration, including cavity width, wall construction, and installation method. Always refer to the individual product datasheet to confirm suitability for a given fire resistance requirement.
Available Sizes
This collection includes common nominal cavity widths. Availability varies by product line:
100mm
125mm
150mm
200mm
Selecting the correct size is essential to ensure proper compression within the cavity and effective fire performance. Nominal cavity widths should always be checked against the manufacturer’s guidance to allow for tolerances and installation conditions.
Product Notes
Where stated on the product page, FIREZERO cavity fire socks in this range are supplied in 1200mm lengths. Always check the individual product listing for the specific dimensions and suitability for your wall build-up.
Benefits of Using Cavity Fire Socks
Cavity fire socks offer a simple and effective way to protect concealed spaces within wall constructions. Key benefits include:
- Helps slow the spread of fire and smoke within cavities
- Supports compliance with building regulations
- Suitable for a wide range of wall types
- Straightforward installation with minimal disruption
- Long-term contribution to passive fire protection
Their versatility makes them suitable for both new-build and retrofit projects.
Choosing the Right Cavity Stop Sock
When selecting a cavity stop sock, consider the following factors:
Cavity Width
The sock should match the cavity dimension to ensure full expansion and sealing.
Wall Construction
Wall type may influence installation method and performance requirements.
Fire Performance Needs
Project specifications and fire strategies may determine whether a standard or higher performance option is required.
Careful selection helps support long-term performance and fire safety.
Reliable Fire Protection for Cavity Walls
These products are commonly specified in UK residential and commercial construction where cavity fire stopping is required as part of a compliant wall build-up. If you need broader context around cavity construction and insulation, see our Cavity Wall Insulation Guide.
Select the appropriate cavity stop sock based on cavity width, wall construction, and the fire performance requirements defined for your project.
