EXOPERM MONO DURO A2 – Class A2 Breather Membrane

EXOPERM MONO DURO A2 is a limited combustible, diffusion permeable monolithic breather membrane designed to meet a high level of fire performance. It has a Reaction to Fire classification of A2-s1, d0.

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  • A2-s1,d0 Reaction to Fire classification
  • Compliant with UK Building Regulations Approved Document B
  • Advanced glass fibre fabric for enhanced structural stability
  • Ideal for high-rise and higher-risk buildings
  • Highly vapour open with an Sd value of 0.09 m
  • Class W2 resistance to water penetration
  • Airtight with an air permeability value of 0,006 m³/m², h, Pa
  • High Permanent UV resistance without cladding, and with 50% and 50mm joints
  • Weather tight
  • Improves energy efficiency of the building
  • Independently tested to EN 13501-1 for compliance


EXOPERM MONO DURO A2 is an external breather membrane of limited combustibility designed for use on the cold side of insulation on façade wall and roof applications.

Suitable for:

  • Facades with open or closed joints
  • Roof applications
  • High-rise, high-risk and public buildings (schools, offices, commercial centres, hospitals, etc.)
  • Commercial and residential developments
  • Timber and steel framed constructions
  • Offsite construction
  • New builds and retrofits

Monolithic Technology

EXOPERM MONO DURO A2 is a limited combustible roof underlay and wind barrier with a monolithic functional layer.

The monolithic functional layer provides enhanced protection for the building envelope:

  • transports vapour to outside
  • is vapour open whilst having excellent waterproofing properties
  • creates a complete wind tight, waterproof membrane that actively expels out any water/humidity unlike most micro-porous membranes that rely on small pores (which have the tendency to block)

Technical Data

WEIGHT EN 13859-2 225 g/m² 
REACTION TO FIRE EN-13501-1 A2-s1,d0
SD-VALUE M EN-13859-2 0.09 M
TENSILE STRENGTH MD / CD EN 13859-2 290 N / 390 N ± 75
NAIL TEAR RESISTANCE MD / CD EN 13859-2 4200 N/3100 N/50mm

1.5m X 50m=75m2 (59-1/16” X 164’-1/2” = 807 SF)