Introducing HYDRA Roof Underlay

Introducing HYDRA Roof Underlay
Published: 9 November 2021

Marshall Innovations logo

HYDRA Roof Underlay is a New Zealand-designed premium roof underlay from Marshall Innovations.

Suitable for all roof types including concrete and clay tiles, pressed metal tiles and profiled metal roofing, HYDRA Roof Underlay is synthetic, fire retardant, absorbent, breathable and self-supporting.

Designed with safety in mind, the underlay also features HYDRA GripSpot for superior slip resistance when working on roofs.

Key Features and Benefits:

  • Breathable, self-supporting, synthetic underlay
  • Fire retardant, flammability index of ≤5 as per AS1530
  • UV Exposure 14 days
  • Tri-laminate offers high strength & lightweight
  • GripSpot provides a slip resistant walking surface
  • HYDRA Breathable Barrier Layer prevents water but allows for transfer of moisture vapour
  • HYDRY Technology bottom layer is designed to absorb moisture in the roof space
  • Suitable on timber and steel frame
  • Suitable with pressed metal and masonry tiles
  • Suitable with profiled metal roofing
  • Suitable in all Wind Zones stated in NZS 3604 up to and Including, extra high
  • HYDRA Roof Underlay is BRANZ Appraised # 1071 (2019) and available in 1250mm x 20m and 1250mm x 40m rolls.

Introducing HYDRA Roof Underlay

HYDRA Roof Underlay completes the Marshal Weatherization System, a system that combines a range of respected products to form a secure construction envelope.

HYDRA Roof Underlay is fitted over the roof framing members. HYDRA Wall or TEKTON Wall Underlay is fixed directly to the outside of the framing. Wall Underlay over the openings is then cut and fixed to the inside face of the framing. Tekton SEAM TAPE is applied over the seams and Protecto Wrap, Super-Stick or the ProtectoSill System is installed around the joinery openings.

TRADE-SEALs are fitted over pipe and conduit penetrations through the building envelope to provide an air and moisture seal.

With superior strength, water holdout and flexibility with ease of installation, the Marshal Weatherization System meets and exceeds the requirements of the New Zealand Building Code (NZBC) Clause B2 Durability and Clause E2 External Moisture.

Marshall Innovations works closely with architects and councils throughout the design phase to provide systems and solutions that deliver a weather tight building envelope. Marshall Innovations technicians are able to visit sites offering advice, product education & support, ensuring systems are installed to manufacturers specification.

Marshall Innovations products and systems are available through leading building merchants and has a nationwide network of certified installers.

Call Marshall Innovations for a chat and to view samples. 0800 776 9727 or visit