Steico Multi UDB

Steico Multi UDBSTEICOmulti UDB is a highly vapour permeable, windproof and weather resistant membrane designed for external building envelopes. It can be used as a roof underlay sarking membrane (including as a supplement to sarking boards), or as a windproof layer behind external wall build ups. Thanks to its robust 3 layer construction and integrated self adhesive sealing zones, it delivers reliable protection from wind and driving rain while still allowing the

STEICOmulti UDB is a highly vapour-permeable, windproof and weather-resistant membrane designed for external building envelopes. It can be used as a roof underlay / sarking membrane (including as a supplement to sarking boards), or as a windproof layer behind external wall build-ups. Thanks to its robust 3-layer construction and integrated self-adhesive sealing zones, it delivers reliable protection from wind and driving rain while still allowing the structure to dry safely outward.

Key Benefits

• Extremely vapour open (sd ≈ 0.02 m) – supports outward drying and moisture-safe construction

• Windproof + weather-resistant for roofs and external wall applications

• Two integrated self-adhesive zones for secure bonding and fast detailing

• Robust 3-layer coated PP non-woven fabric with high tear resistance

• W1 resistance to water penetration (including after artificial ageing)

• Outdoor exposure up to 12 weeks (during construction phase)

• Suitable as a temporary roof cover for up to 4 weeks (when correctly detailed)

Typical Uses

Roofing

• Sarking membrane / roof underlay

• Diffusion-open formwork membrane supporting breathable roof build-ups

External Walls

• Windproofing layer within breathable external wall systems (behind cladding / façade systems)

Refurbishment / Retrofit

• Can also function as an airtight layer within compatible refurbishment solutions, where detailing and continuity are correctly achieved

Installation Notes (Best Practice)

• Lay with the printed side facing the installer

• Install parallel to the eaves, starting from the bottom

• Maintain minimum 100mm overlaps

• Fix only within the overlap zone (e.g., staples/clips)

• Activate the self-adhesive strips only after fixing the sheet in position

• On roofs, secure with STEICOmulti nail tape and counter battens

• Where used as windproofing or airtightness, all joints/edges/penetrations must be bonded appropriately using STEICO system accessories