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HYDRA Flexible Wall Underlay

An absorbent, synthetic, flexible building underlay for use under wall claddings.

A Plain white-coloured, non-woven scrim with a polymeric laminated face, and with the HYDRA Logo printed on the outer face.

Key Features
  • BRANZ appraised
  • Excellent tear strength to withstand heavy winds
  • Provides temporary weather protection
  • Suitable for timber and steel frames
  • Use with claddings and rigid wall underlays
Scope of Use
  • Suitable and appraised for use as a wall underlay on steel and timber framed buildings
  • Suitable and appraised for use over rigid wall underlays on steel and timber framed buildings
  • Appraised for use on buildings subject to specific weathertightness design
Limitations on Use

Used as secondary weathertightness protection, and also to provide some protection of framing and structure during construction, however must not be left exposed to weather or UV for more than 60 days. 

Statement of Building Code Compliance

NZBC Clauses:

  • B2 Durability: B2.3.1 (a), not less than 50 years, B2.3.1 b), 15 years and B2.3.2
  • E2 External Moisture: Performance E2.3.2. When used as part of the cladding system, HYDRA Wall Underlay will contribute to meeting this requirement
  • F2 Hazardous Building Materials: F2.3.1. HYDRA Wall Underlay meets this requirement and will not present a hazard to people

See BRANZ Appraisal 1072 for full information

In-Service History

HYDRA Wall Underlay has been available in New Zealand since 2020, however been available much longer internationally.

Other Performance Attributes
  • Excellent tear strength to withstand heavy winds
BRANZ Appraised
BRANZ Appraised
BRANZ Appraisal 1072

1072 [2019]

Marshall Innovations provide weathertight solutions from below ground to pre-cladding.

Product Enquiries

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