AIM Party Wall Fire Closers

Semi-rigid Rockwool stone wool to polythene DPC Cavity Closers for the junctions at party walls. The AIM Party Wall Fire Closer has been designed to provide at least 1 hour resistance to the spread of fire past the party wall of adjoining buildings. It also significantly reduces flanking sound transmission within masonry wall cavities. Rockwool red logo    

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  • Helps in achieving the building regulations and the NHBC requirements
  • Thermal Conductivity: λ = 0.034W/mK
  • Ozone depletion potential of zero. No CFCs or HCFCs used in manufacture
  • Global warming potential = zero

Rockwool stone wool insulation

  • Length: 1200mm
  • Width: 260mm
  • Thickness: 50, 65, 75, 90, 100, 120mm

DPC Polythene

  • Length: 1300mm
  • Side overlap: 40mm
  • End overlap: 100mm


Fire Performance

The performance of the AIM fire protection range has been tested to BS 476 part 20 and assessed by Warrington Fire Research Centre. The AIM Party Wall Fire Closer will provide a fire rating of 1 hour, provided that the bearing width of the closer on each side of a cavity party wall is at least 75mm.

AIM mineral wool products are non combustible to BS 476 part 4, rated Class 1 Surface Spread of Flame to BS 476 part 7 and comply with the performance requirements of Class O of the Building Regulations (does not apply to the DPC).

The DPC conforms to BS 6515 (1984).


AIM Party Wall Fire Closer may be used to reduce the passage of flanking sound through masonry cavities.

It complies with Approved Document E 2003 to the Building Regulations and with the requirements of Robust Details.


The AIM Party Wall Fire Closer should be installed in the external cavity wall with an equal overlap to either side of the party wall cavity. For 1 hour fire rating, the bearing on either side must be at least 75mm.

The Fire Closer should be fitted with the DPC overlap at the bottom. At the top of the Party Wall Fire Closers, the DPC should be extended to the inner leaf of the wall to form a cavity tray or sealed to the underside of the lintel.

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