Fire Rated Cavity Closers


The Manthorpe G249R Half-Hour Fire Rated Cavity Closer has been designed for use where a fire barrier is required to seal cavities around window and door reveals of a building.

  • Description & Key Features

    Product Description

    The Manthorpe G249R ½ Hour Fire Rated Cavity Closer is suitable for use in rebated openings where a fire barrier / fire stop is required to seal cavities around window and door reveals of a building. In this construction the frame is positioned behind the outer leaf and is suitable for use in exposed categories up to and including very serve as defined in table 10 of BS5628 Part 3 which covers all exposure zones in the United Kingdom.

    The unique compressible clip feature allows the product to expand within the cavity creating a continuous seal to any varying width. The enclosed box design incorporates a fibre insulating core which provides an economical solution to cold bridging acting as a thermal cavity closer,
    DPC and ½ hour fire barrier.

    It is manufactured in four sizes that suit cavity widths varying from 50mm to 130mm in size. It can be easily installed either in new build or refurbishment situation with no special fixing requirements or tools. The Manthorpe G249R ½ Hour Fire Rated Cavity Closer has been designed to comply with Building Regs Part L and Scottish Technical Standards Part D.

    Key Features

    • Half hour fire rated
    • Rigid extruded UPVC sections
    • Unique variable clip feature
    • Compressed mineral fibre wool insulation
  • Technical

    Fitting Requirements

    Brick up to sill height, cut and fit the sill closer. Cut the jamb lengths 75mm oversize and trim the flanges back to allow them to overlap the sill closer once fitted.

    Continue to brick up the wall, securing all pieces of the cavity closer by plugging and screwing through the larger flange into the internal leaf.


    Warrington Fire - G249 Cavity Closer - Test Report No. 134212.pdf

    Regulations & Standards

    BS 5250:2011 Control of condensation in buildings.

    Approved Document L1 & L2:
    Conservation of fuel and power.

    NHBC Technical Guidance 6.7:
    Doors, Windows & Glazing

    BRE Digest Report 262: Thermal Insulation: Avoiding Risks.

    BRE Information Paper IP 1/06: Thermal Bridging at Junctions & Openings

  • Specifications

    Size Information

    Length 2.4m

    Cavity width from 50mm to 130mm





    Quantity Information

    3 lengths per pack

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