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Designed to close masonry cavities for fire, thermal and acoustic purposes; reduces cold bridging when closing cavities at door and window frames. Can accommodate movement in the building and allow for any irregularities in the cavity clips per length.


  • Rockwool stone wool: 1200 mm long, available in three widths and five thicknesses.
  • Damp proof course polythene: 1300 mm long, 40 mm side lap and 100 mm end lap. Conforms to BS 6515:1984.

Fire performance to BS 476-20:

Four hours (maximum), assessed by Warrington Fire Reach Centre.

Surface spread of flame to BS 476-7:

Class 1 rated.


Can be used to prevent the passage of flanking sound within masonry cavities and complies with Building Regulations (E&W) Approved Document E 2003 and the requirements of Robust Details.


Ozone depletion potential of zero. No CFCs or HCFCs used in manufacture.

NBS Specification

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This product is associated with the following NBS Create clause:
45-45-70/465 Sleeved mineral wool cavity barriers

NBS Specification

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This product is associated with the following NBS clauses:

Product specification

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+44 (0)1293 582400

Product reference

Cavity Fire Closers


[100 mm]
[150 mm]
[190 mm]


[20 mm]
[50 mm]
[65 mm]
[75 mm]
[100 mm]

Manufacturer details

Unit H3,
Sussex Manor Business Park ,
Gatwick Road ,
Crawley ,
West Sussex , RH10 9NH
Tel +44 (0)1293 582400
Fax +44 (0)1293 552690
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