Marley Universal non-breathable underlay is a lightweight (116g/m²), high-performance membrane for pitched roofs. Supplied in 1m x 45cm rolls with integrated tape for sealing laps, the underlay is fully compliant with BS 5534 and suitable for all UK wind zones 1 - 5.
Marley underlays are manufactured using the latest materials and processes, and each incorporates a number of useful features that assist in ensuring installation that is not only correct, but also compliant with the latest British Standards.
| Material | PP 3 layers |
| Weight | 116 (-10+10) |
| Resistance to water penetration | W1 |
|
Batten gauge |
<250 (Zone 1-5) <354 (Zone 1-5) |
| Adhesive tapes | 1 |
| Tests | CE, BBA, IBA approved |
| Tensile strength (N/50mm) | |
| Before artificial aging |
MD 280 (-70) CMD 170 (-50) |
|
After artificial aging
|
MD 240 (-70) CMD 140 (-50) |
| Elongation (%) | |
| Before artificial aging |
MD 60 (-20)% CMD 70 (-20)% |
|
After artificial aging |
MD 40 (-20)% CMD 50 (-20)% |
|
Tear resistance
|
MD 140 (-40) CMD 130 (-40) |
| Flexibility at low temperature | -40oC |
| Equivalent air layer thickness (Sd) | 15 |
| Reaction to fire | Class E |