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Party Wall Fire Closers -

Verified by manufacturer 2 months ago


Semi-rigid Rockwool stone wool laminated to polythene damp proof course cavity closers for the junctions at party walls junctions.

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  • For resisting fire spread at the junction of party walls.
  • Closes masonry cavities for fire, thermal and acoustic purposes.
  • For cavities in excess of 100 mm, please use the AIM Wall Cavity Barrier complete with polythene DPC to either side of the party wall junction.


AIM Party Wall Fire Closers are semi-rigid Rockwool stone wool laminated to a polythene DPC. They have been designed to provide at least one hour resistance to the spread of fire and smoke in all three directions at the party wall junction. It also significantly reduces flanking sound transmission within external wall cavities.

The Party Wall Fire Closer is supported with test evidence to show its performance in cavity walls constructed from a variety of different substrates including masonry, many timber frame structures and SFS / through-wall systems.

Features and benefits:

  • A section of Rockwool stone wool insulation laminated to a polythene DPC.
  • DPC polythene conforming to BS 6515.
  • Stone wool and DPC dimensions to suit most cavity wall/ party wall junctions.
  • AIM Party Wall Fire Closer is supplied pre-cut in 1200 mm lengths, 260 mm wide and thicknesses depending on the fire rating required. The product supplied is as required to fill the void.
  • The pre-cut product is supplied with fixing clips if required.
  • Closes cavities up to 100 mm thick.
  • The product has been tested to BS EN 1366-4 to provide up to 120 minutes integrity and insulation.
  • Up to two one hour fire resistance in all three directions.
  • Closes masonry cavities for fire, thermal and acoustic purposes.
  • Now with test evidence that supports the use within a wider range of substrates.
  • The pre-cut product is supplied with the required fixing clips.

General information







1200 mm


260 mm


Manufacturer guidance

Bespoke widths available upon request.


Manufacturer guidance

  • Thickness.
  • Bespoke thicknesses available on request.


Pr_25_80_81_51 Mineral wool fire-stoppingPrimary


P12/360 Mineral wool rigid batts

P12/40 Mineral wool rigid batts

Product range

Fire Barriers

Specification data - Mineral wool fire-stopping




DPC polythene to BS 6515:1984.



Fire performance

Masonry to masonry: EI 120/120 minutes; Masonry to softwood: EI 60/30 minutes; Masonry to OSB: EI 60/60 minutes; Masonry to CP Board/ SFS: EI 60/60 minutes.

Guidance for specification option:

Application: integrity/ insulation.

Sound insulation rating

To ISO 10140-2, RW 14 db (75 mm bearing), RW 18 db (100 mm bearing), RW 23 db (140 mm bearing).

Guidance for specification option:

Complies with Approved Document E 2003 to the

Building Regulations.


50 mm.

65 mm.

75 mm.

90 mm.

100 mm.

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Manufacturer guidance

Bespoke thicknesses available upon request.


0.034 W/mK.

Semi-rigid DPC

Length: 1300 mm, Side overlap: 40 mm, End overlap: 100 mm.


Guidance for specification option:

Insert requirements.

Manufacturer guidance

Non-standard DPC offsets and widths available upon request.


AIM fire barriers are chemically inert, will not sustain vermin and do not encourage the growth of rot, fungi, moulds or bacteria.

Guidance for specification option:

Rockwool stone wool has been proven in service for over 60 years, in a wide range of climates and degrees of exposure. It will generally perform effectively for the lifetime of the building, plant or structure.


Compatible with all normal building materials.


Global warming potential = zero.

Guidance for specification option:

AIM fire barrier products are manufactured from stone wool insulation which is universally recognised as being a sustainable and environmentally friendly material.


Not required.

Acrylic fire rated intumescent mastic.


AIM Party Wall Fire Closer Technical Guide 2022

AIM Party Wall Fire Closer Technical Guide 2022

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