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Lamella Firebreak
Data Sheet


A/F Party Wall DPC consists of a length of flexible mineral wool slab fully bonded to 500 micron polyethylene damp proof course. The damp proof course has a 40mm and 300mm flange on the long sides and a 100mm flange on one end.


Horizontal DPC Cavity Closer is designed to minimise sound transmission and prevent fire penetration through the wall cavity adjacent to separating floors.


  • Insulation length : 1200mm
  • Insulation width : 260mm
  • DPC length : 1300mm
  • DPC width : 600mm
  • Insulation thickness : 50mm 60mm 75mm 80mm
    90mm 100mm 110mm

Other sizes can be manufactured to order

Standards and Performance

The mineral wool is non-combustible to BS476: part 4:(1984). The DPC conforms to BS6515 (1984).

The correct use of A/F Party Wall DPC will exceed the requirement to provide a 30 minute cavity fire barrier as defined in Table A1 of Appendix A to Approved Document B of Building Regulations 1991.

The product has been independently tested adopting procedures and criteria from BS476 : part 20 : (1987) and achieved 1 hour fire resistance.
A/F Party Wall DPC complies with the robust details accepted to provide a solution which satisfies the Approved Document E (2003 Edition) of the Building Regulations relating to the transmission of sound.


Horizontal DPC Cavity Closer should be fitted during the brickwork / blockwork stage of the building process. The product should be fitted with the DPC against the inner face of the outer brickwork at the level of the separating floor. The product is positioned with the wide DPC flange uppermost and embedded into the inner blockwork mortar layer. The product should be supported by the wall ties that join the inner and outer leaf.

A/F Party Wall DPC is supplied in strong polyethylene bags for on site protection. Care should be taken to keep the product dry prior to installation. Some local delamination may occur during handling.
This does not detract from the performance of the product.

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