STEICOmulti Membra 5 - Vapour Control & Airtight Membrane - 1.5m x 50m roll

STEICOmulti Membra 5 is a reinforced, vapour-retarding membrane designed for internal use in roof, wall, and ceiling constructions. It is engineered to create a permanent airtight seal for the building envelope while managing the flow of water vapour into the insulation layer to prevent interstitial condensation. STEICOmulti membra 5 is the critical internal layer that manages moisture and stops drafts. It is a high-performance vapour control layer (VCL) that balances airtightness with a calculated fixed vapour resistance.

CHARCTERISTICS

• With a fixed sd value of 5m, it is a vapour retarder rather than a total vapour barrier. This is optimised for timber-framed structures, as it limits vapour ingress during the winter but allows for a degree of back-drying towards the interior in the summer.
• Unlike standard polythene sheets, membra 5 is reinforced with a high-strength mesh (scrim). This makes it incredibly robust during installation and capable of withstanding the pressure of blown-in insulation like STEICOzell.
• The membrane is slightly translucent, which is a massive help on-site. It allows installers to see the timber studs or rafters behind the membrane, making it much easier to ensure fixings are driven into the structural timber.
• When combined with the STEICOmulti tape range, it forms a continuous, airtight layer that is essential for achieving low air-permeability scores and reducing energy loss.
• It features printed grid lines and overlap markers, ensuring that the required 10cm overlap is maintained accurately across the entire installation.

APPLICATION

• Timber Frame Construction: Fixed to the warm side of the studs before the internal service void and plasterboard are installed.
• Roof Renovations: Installed internally across rafters to provide airtightness and vapour control in loft conversions.
• Ceiling Joists: Used in cold-roof constructions to prevent moist internal air from rising into the cold loft space.

INSTALLATION

• For a perfect airtight seal, always ensure that the membrane is installed without tension.
• When sealing the overlaps with STEICOmulti tape P, use a roller to apply firm pressure; this activates the pressure-sensitive adhesive and ensures a permanent bond that will last the lifetime of the building.