





Permo® sec / Permo® sec SK
Very strong and robust metal roof underlay
- 5-layer fleece foil combination with reinforcement grid and PP monofilament mesh
- Covers irregularities within roof deck that could de-form metal roof covering
- Fully waterproof secondary barrier to moisture penetration
- Fully vapour permeable
- Acoustic value of 8db helps reduce the transmission of external structure borne sounds
- Prevents condensation that occurs on the underside of the metal roof covering from re-entering the roof structure
- Provides an air space below zinc coverings to allow protective oxidation to form

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Product information
Permo® sec is a very strong and robust vapour permeable waterproofing barrier that is installed as a separating layer between copper, zinc, aluminium and stainless steel standing seam roof finishes and the supporting deck.
Technical data
Material | Outer layer of polypropylene mesh bonded to a vapour permeable membrane. 5-layer fleece foil combination of polyolefin, hydrophobic treatment and PP monofilament mesh |
Weight | 550g/m² |
Thickness | 0.85cm |
Water vapour transmission EN 12572 (sd value) | 0.03m |
Reaction to fire EN 13501-1, EN 11925-2 | E |
Water column, EN 20811 | > 3000mm |
Resistance to water penetration EN 1928 | W1 |
Resistance to air penetration | < 0.1m³/m² h 50 Pa |
Tensile strength longitudinal / transverse EN 12311-1 | 320N/50mm | 290N/50mm |
Elongation longitudinal / transverse EN 12311-1 | 5% | 5% |
Resistance to tearing (nail shank) longitudinal / transverse EN 12310-1 | 280N | 340N |
Melting point | >200°C |
Acoustic damping value | 8db |
Resistance to temperature | -30ºC to +80ºC |
UV-resistance1) | 4 months |
1) Natural weathering Central Europe |