NBS Source
illbruck ME501 Duo Window Membrane HD


Provides a high performance seal to the perimeter joint between the window/ curtain wall and the construction reveal. The membrane is suitable for interior and exterior use and can provide an airtight or weathertight (but breathable) seal. The product meets the recommendations of the RAL Quality Assurance Association for windows and doors. It is successfully tested by MPA Hannover to BS EN 1026 (air tightness) and BS EN 1027 (weather tightness). The membrane is fixed to the window with either illbruck SP525 Adhesive or a gasket and to the construction reveal with SP525 adhesive.


  • Available with gasket options for fixing to profile.
  • Complies with principle of ‘inside tighter than outside’ in order to facilitate efficient vapour control - avoids interstitial condensation.
  • Excellent drying potential.
  • High strength, tear resistant.
  • UV stable; will tolerate up to 12 months direct exposure prior to covering.
  • Membrane can be applied before or after window installation to suit on-site details and programming.

General information


Tear-proof, polyethylene copolymer film with woven fabric


Pr_25_57_65_60 Plastics sheetsPrimary


H11/772 Curtain walling joint assembly sealants

L10/75 Sealant joints

L10/810 Sealant joints

L20/80 Sealant joints

L20/820 Sealant joints

Specification data - Plastics sheets

Product Reference

illbruck ME501 Duo Window Membrane HD


Insert requirement, available 60–1500 mm without gasket or 150 and 300 mm with gasket.


Not required


3–5 mm groove width.


5–7 mm groove width.


7–10 mm groove width.

Standard product features


Tear-proof, polyethylene copolymer film with woven fabric.



Technical properties:

  • Airtightness (to BS EN 1026): < 0.1 m³/m²h.
  • Building material class (to DIN 4102): B2.
  • Temperature resistance: -40 to +80°C.
  • Water vapour permeability (sd value, to DIN 4108-3): 0.3 to 20 m, depending on average atmospheric humidity.
  • Weathertight against driving rain (to BS EN 1027): > 600 Pa.

Product Options


As an alternative fixing method to the frame, there are four gasket options which can be used, dependent on a suitable groove on the frame profile. The gasketed membrane is fixed to the construction material using illbruck SP525 Adhesive.

Also available as ME501 VV with full face self-adhesive backing.

Third party certifications

  • 12/4891 : Accredited in isolation or as part of the illbruck 'i3 System'

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