Consists of a microporous water resistant film, sandwiched between two layers of shrink resistant spun-bonded polyolefin.
In Roof Applications - Intended for use as a alternative to conventional kraft paper roof underlay, which are fixed over timber or steel framed roofs and to assist in the moisture management of roof cladding systems.
In Wall Applications - Intended for use as an alternative to conventional kraft paper wall underlays, which are fixed over timber or steel frame walls in order to limit the entry of wind into building cavities.
Scope of use
Covertek 405 Fire retardant absorbent breathable synthetic non-woven roof underlay can be used as a roof underlay on buildings within the following scope:
- the scope limitations of NZBC Acceptable Solution 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 roof cladding; and,
- situated in NZS 3604 Building Wind Zones up to, and including “Very High” when used in walls. May be used in all wind zones including "Extra High" when used as a roof underlay
New Zealand Building Code (NZBC)
The product will, if employed in accordance with the supplier's installation and maintenance requirements, assist with meeting the following provisions of the building code:
- Clause B2 Durability: Performance B2.3.1(a), B2.3.1(b), B2.3.2
- Clause E2 External moisture: Performance E2.3.2
- Clause F2 Hazardous building materials: Performance F2.3.1
The product meets the requirements set out in the following documents, or relevant parts of cited standards within the documents:
Meets the requirements of the NZ building Code E2/AS1 table 23 as an alternative solution.
The product has and can make available the following additional evidence to support the above statements:
In climatic regions where condensation risks are high, such as cold or high humidity areas, care needs to be taken in specifying the correct design and installation to prevent moisture build-up in the roof cavities. Factors which adversely affect the condensation risk in roofing systems include;
- Humid, and/or cold climatic regions
- Warm/Skillion roof construction
- Low roof cavity air volume and restricted air movement
- Omitting Vapour Control Layers
- Ceiling penetrations and entry of warm air into roof cavities
- Occupancy activities which have high moisture loading on conditioned spaces
- Low pitched roof
- Bulk insulation
- Building structures ability to naturally dry Construction Moisture
Skillion and Warm Roof Construction are particularly sensitive to moisture accumulation and the design and installation
For additional information or advice www.thermakraft.co.nz
LONG-RUN METAL ROOFING / VERTICAL OR HORIZONTAL INSTALLATION METHOD
ROOF can be Direct or cavity fixed and must be installed in a manner that prevents ponding of water, and span no more than 1200mm without additional support.
The minimum roof pitch is 3 degrees On roof pitches below 10 degrees Covertek 405 must be supported if run vertically.
Must be laid firmly (tight) without creases.
All laps either vertical or horizontal must have a minimum of 150mm lap.
Fix using stainless steel 8-12mm staples or 20mm flat head clouts, or appropriate proprietary fastenings.
Click here to download the Thermakraft warranty statement.
Covertek has no known negative environment conditions
Covertek has no VOCs in manufacture installation or use
Covertek is recyclable at end of life with no harmful residue
||New Zealand Made