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DriStud RU 24: Low-Cost, Self-Supporting Synthetic Roofing Underlay

In January TCL Hunt launched a new range of synthetic roofing underlays — two fire retardant and two non-fire retardant. These roofing underlays are specifically engineered for New Zealand and are all CodeMark certified.

DriStud RU24 is a non-fire retardant self-supporting synthetic roofing underlay. The non-fire retardant range was developed to provide a low-cost synthetic option where bituminous based roofing underlays would be traditionally used. All DriStud roofing underlays are designed to act as the second line of defence of the roof envelope and also contribute to the overall moisture management in roof spaces.

The use of synthetic roofing underlay has gradually increased over the past couple of years as it is easier to use, quicker to install and it does not shrink or tear like Kraft paper when wet.

With installation taking less time (costing less in labour) DriStud RU24 recovers the cost difference in material almost immediately. Although it is not classified as 'fire retardant,' DriStud RU24 has a Fire Index of 9.


RU24 is a non-fire retardant self-supporting black faced synthetic roofing underlay. It is a tri-laminate consisting of engineered synthetic materials and it is water resistant and vapour permeable.

It is intended for use on new and existing buildings in wind zones up to and including 'Extra High', as defined in NZS 3604:2011.


  • CodeMark certified
  • Self-supporting
  • Can be installed over timber and steel roof framing
  • Breathable
  • Absorbent
  • Durability: 50 years
  • Can be direct fixed behind all claddings
  • Fire resistant — FR Index 9
  • Easier and quicker to install with 150mm lap lines 
  PropertyTest MethodRoofing Underlay RequirementsRU 24 Non-Fire Retardant, Self Support Roofing UnderlayRU 22 Non-Fire Retardant, Heavy Weight Roofing Underlay
1 Water Vapour Resistance ASTM E96 Procedure B ≤ 7MN s/g Pass Pass
2 Absorbency AS/NZS 4201: Part 6 ≥ 150 g/m Pass Pass
3 Water Resistance AS/NZS 4201.4:1994 ≥ 100mm head water Pass Pass
4 Flammability AS 1530.2:1993 AS 1530.2:1993 Index 9 Index 17
View more information on DriSpace, including contact details.
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