STEICOmulti Membra 5 is a robust, diffusion-open vapour control membrane designed for the airtight internal sealing of roof, wall and ceiling build-ups. With an sd-value of 5.0m, it helps control water vapour movement from inside the building, while still supporting moisture-safe, breathable timber-frame and warm roof constructions.
Made from a 3-layer, coated PP non-woven fabric with mesh reinforcement, it is highly tear resistant, easy to handle on site, and suitable for use with both insulation batts and blown / injected insulation systems.
Key Benefits
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Airtight vapour control layer (VCL) for internal applications
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Diffusion-open performance (sd = 5.0m) – ideal for modern breathable build-ups
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Robust + flexible 3-layer membrane, mesh reinforced
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High tear resistance for reliable installation on busy sites
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Suitable for blown-in / injected insulation and insulation batts
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Translucent membrane helps visual checks during installation (flush contact to insulation)
Typical Uses
Internal airtightness layer for:
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Pitched roofs (warm roofs / insulated rafters)
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Timber frame walls
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Ceiling constructions and attic conversions
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Retrofit projects requiring controlled vapour management
Installation Notes (Best Practice)
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Install with the printed side facing the installer
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Lay parallel or at right angles to rafters, with minimum 100mm overlaps
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Ensure the membrane is flush to the insulation with no gaps (important for airtightness)
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Fit tension-free and avoid creases
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Seal all overlaps, junctions and penetrations using STEICO system tapes and accessories
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Add mechanical support (e.g. battens) promptly where required to support insulation weight
