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Thermakraft CoverTek 407

Thermakraft CoverTek 407 is a fire retardant self supporting synthetic building underlay for the 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 as an alternative to kraft paper roofing 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.

Key Features
  • High water barrier
  • Fire retardant
  • Breathable
  • Absorbent
  • Self-supporting
  • Strong and durable
  • CodeMark and BRANZ appraised
Categories / Ranges
Wraps, Underlays and DPCs Roof
Scope of Use

Thermakraft CoverTek 407 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
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 407 meets these requirements.

Clause E2 External Moisture: Performance E2.3.2. When used as part of the cladding system, Thermakraft CoverTek 407 will contribute to meeting this requirement.

Clause F2 Hazardous Building Materials: Performance F2.3.1. Thermakraft CoverTek 407 meets this requirement and will not present a health hazard to people.

Flammability Index

Thermakraft CoverTek 407 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.

Data Sheet

Issue 6, June 2020

Quick Reference Guide

Issue 2, Nov 2019

CodeMark Certificate


Independent Appraisal (BRANZ)

No.651 [2019] 26 Jun 2020

Thermakraft Warranty Statement

Issue 2, Nov 2019

Installation and Operation

Issue 2, June 2020

Thermakraft Ltd are a leading New Zealand manufacturer of Synthetic and Bituminous underlays for the roof and wall with over 30 years experience

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