Cavity Fire Closers

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.

General information

Uniclass 2015

Pr_25_80_80_79 Sleeved mineral wool cavity barriersPrimary


P12/360 Mineral wool rigid batts

P12/40 Mineral wool rigid batts

Specification data - Sleeved mineral wool cavity barriers

Product Reference

Cavity Fire Closers


100 mm

150 mm

190 mm


20 mm

50 mm

65 mm

75 mm

100 mm

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