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Viking Gemini APP TorchOn Membrane

Viking Gemini APP is a robust and versatile membrane system ideally suited to New Zealand's North Island (except the Central Volcanic Plateau) and the Pacific Islands.

Viking Gemini APP consists of a 3mm thick base sheet installed on a bitumen-primed substrate. This provides a building's secondary waterproofing layer, on top of which a 4mm ceramic chip cap sheet is then 'torched' to provide the primary waterproofing and UV resistant layer.

Key Features
  • Cold Flexibility Range: -10°C up to +140°C
  • Total Thickness: 7mm
  • Roll Width: 1m
  • Roll Length: 10m
  • Colour: Black and Grey
  • Installed only by Viking Licensed Applicators
  • UV resistant
  • Thermal ageing resistance
  • Dimensional stability
  • Tensile resistance
  • Overlay option
  • 20-year product warranty
  • BRANZ Appraised (Appraisal No. 948)
NZ-Owned Business
NZ-Owned Business
Scope of Use

Viking Gemini APP is suited to tricky / confined roofs where it can be 'bled' in to vulnerable areas such as tight corners and awkward areas susceptible to leaks such as roof penetrations, internal corners and gutter junctions.

It is suitable for low-slope roofs (flat or curved), gutters and parapets, waterproofing beneath a floating deck, inland and coastal conditions, commercial and residential buildings.

Viking Gemini APP Waterproofing Membrane has been assessed as a roof waterproofing membrane on buildings within the following scope:

  • The scope limitations of NZS 3604:2011 and NZBC Acceptable Solution E2/AS1, Paragraph 1.1; or,
  • The scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area when subject to specific structural design; and,
  • Situated in NZS 3604:2011 Wind Zones, up to and including Extra High; and,
  • With substrates of plywood or suspended concrete slab; and,
  • With a minimum fall for roofs of 1:30 (2 degrees)

Viking Gemini APP Waterproofing Membrane has also been assessed for use as a roof waterproofing membrane on buildings within the following scope:

  • Subject to specific structural and weathertightness design situated in wind pressures up to a maximum design differential ultimate limit state (ULS) of 6 kPa: and,
  • With substrates of plywood or suspended concrete slab
Limitations on Use

Viking Gemini APP (Atactic Polypropylene) is primarily designed to be installed in the Pacific Islands and NZ's Climate Zones 1 and 2 (North Island except for Central North Island Volcanic Plateau).

The system must be installed by a Viking Roofspec Trained and Approved Installer.

Statement of Building Code Compliance
  • Clause B1 STRUCTURE: Performance B1.3.1 and B1.3.4 (b) (c) (d) (e) for the relevant physical conditions of B1.3.3 (p). Viking GM Gemini A.P.P Waterproofing Membranes meet this requirement.
  • Clause B2 DURABILITY: Performance B2.3.1 (b), 15 years. Viking GM Gemini A.P.P Waterproofing Membrane meet this requirement.
  • Clause E2 EXTERNAL MOISTURE: Performance E2.3.1, E2.3.2 and E2.3.7 (b) and (c). Viking GM Gemini A.P.P Waterproofing Membrane meets these requirements.
  • Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1. Viking GM Gemini A.P.P Waterproofing Membrane meets this requirement and will not present a health hazard to people.
Other Performance Attributes
  • BRANZ appraised (no. 948, 2017);
  • Viking Gemini APP is backed by a 20-year product warranty and for specific projects, is eligible for Viking's Full System Warranty, which covers the product and installation in one document;
  • The bitumen used in Viking Gemini APP is a bi-product of the oil refining process, providing a constructive use of this waste product;
  • A Viking Gemini A.P.P roof can be overlaid at the end of its useful life, avoiding the dumping of the old roof and the filling of landfills with inorganic waste.
B1 Structure compliant
B2 Durability compliant
E2 External Moisture compliant
External Moisture
F2 Hazardous Building Materials compliant
Hazardous Building Materials
BRANZ Appraised
BRANZ Appraised
Viking Products Material Safety Data Sheets


Product Technical Statement
Specification Clause (Masterspec)
BRANZ Appraisal 948

948 [2017] amended 2019

CodeMark Certificate

GM-CM30092- RevA

Code of Practice
Find an Approved Installer
Substrate Checklist: Concrete
Substrate Checklist: Plywood
Substrate Checklist: Strandsarking
Maintenance Instructions
Brochure: Viking TorchOn
Additional Information
Case Study: Protecting the Sounds of Music
Case Study: TorchON Protects Home Below and Above Ground
Case Study: TorchON Protects Roof and Deck
CAD/PDF Details
Viking Roof Garden Details Full Set
Viking Torch-On Details Full Set

For over 50 years, Viking Roofspec have supplied roofing and waterproofing materials, and combining leading-edge function with design flair to keep water out — for good.

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