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Thermakraft CoverTek 405 — Roof & Wall Underlay

Thermakraft CoverTek 405 is a fire retardant self supporting synthetic roofing underlay for use under all claddings. Consisting of a microporous water resistant film, sandwiched between two layers of mould and shrink resistant spun-bonded polyolefin. It is intended for use as an alternative to the conventional kraft paper roof underlays, which are fixed over timber or steel framed roofs in order to limit the entry of wind into the roof cavity and to assist in the moisture management of the cladding system. Ideal for use when underlay will be left exposed as branding will not be visible

Key Features
  • Suitable with masonry tile roof cladding, metal tile, and profiled metal roof cladding
  • May be run to any length
  • Suitable for use under dark coloured roofs
  • Has a 150mm lap line printed on each edge
  • Can be used on roofs up to and including NZS 3604 Extra High wind zones
  • Is fire retardant
  • Unaffected by LOSP treated timber
  • Recyclable with no VOCs
  • Tear resistant and strong
Scope of Use

Thermakraft CoverTek 405 Fire Retardant Self-Supporting Roof Underlay has been appraised for use as a self-supporting roof underlay on buildings within the following scope:

  • the scope limitations of NZBC Acceptable Solutions E2/AS1, Paragraph 1.1 with regards to building height and floor plan area; and,
  • with masonry tile roof cladding; and,
  • with metal tile and profiled metal roof cladding; and,
  • situated in NZS 3604 Wind Zones up to, and including Extra High
Limitations on Use

Suitable for use as a roof underlay:

  • When used as a roof underlay is suitable for use all wind zones of NZS 3604
  • Is suitable for use as an Air Barrier in unlined walls
  • Suitable with masonry tile roof cladding
  • With metal tile and profiled metal roof cladding
  • Can be used as a roof underlay on roofs of 10 degrees pitch or greater. Requires support
  • Will provide temporary weather protection during construction (roofs 7 days) same day coverage recommended
  • May be installed in adverse conditions
  • May be run to any length, including under dark coloured roofs
  • Has a 150mm lap line printed on each edge
NZS 3604 Wind Zone Extra High suitable
Extra High Wind Zone
Statement of Building Code Compliance

Clause B2 Durability: Performance B2.3.1 (a), not less than 50 years, B2.3.1 (b), 15 years and B2.3.2. Thermakraft CoverTek 405 meets these requirements.

Clause E2 External Moisture: Performance E2.3.2. When used as part of the cladding system, Thermakraft CoverTek 405 will contribute to meeting this requirement.

Clause F2 Hazardous Building Materials: Performance F2.3.1. Thermakraft CoverTek 405 meets this requirement and will not present a health hazard to people.

Flammability Index

Thermakraft CoverTek 405 Roof Underlay has an AS 1530 Part 2 flammability Index of not greater than 5 and therefore meets the requirements of NZBC Acceptable Solutions C/AS2 to C/AS6, Paragraph 4.17.8 b), for the surface finish requirements of suspended flexible fabric used as an underlay to exterior cladding that is exposed to view in occupied spaces. It may therefore be used with no restrictions in all buildings.

Other Performance Attributes
  • BRANZ Appraisal 743
  • CodeMark Certificate 30030
  • Recyclable with no VOCs
BRANZ Appraised
BRANZ Appraised
Data Sheet

Issue 6, Sep 2022

Quick Reference Guide


Thermakraft on Masterspec
BRANZ Appraisal 743

No.743 [2019] 24 May 2024

CodeMark Certificate

CMNZ 30030 RevH

Installation and Operation

Issue 3, Sep 2022

Kingspan Thermakraft Warranty Statement

Issue 3, Aug 2022

Kingspan are New Zealand’s leading provider of high-performance insulation products and complementary Thermakraft range of premium wall & roof underlay products, flashings tapes & underlay mesh.

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