THERMAKRAFT 220
Lightweight synthetic wall wrap.
Thermakraft 220 is a lightweight, fire retardant wall underlay for use behind exterior wall cladding. It is designed to keep water out while allowing water vapour to escape the wall cavity.
Product Specifications
Thermakraft 220 comes in two roll sizes:
| Width | Length | Coverage |
|---|---|---|
| 1370mm wide | 55m long | 75m² coverage * |
| 2740mm wide | 36.5m long | 100m² coverage* |
*Note: M2 is the roll size for actual coverage, allow for laps and joins.
Product Description
Thermakraft 220 is a two-layer laminated wall underlay combining a Polyester layer with a high quality vapour permeable film. This allows water vapour to pass through from inside the wall cavity whilst water from the exterior is kept out. The product is simply fixed to timber framing using construction staples and is made to stretch around corners providing a tight fit and reducing the risk of staple tear. It will provide temporary weather protection during construction. (Max 42 days).
Scope of use
Thermakraft 220 can be used as a wall underlay on both residential and commercial buildings within the following scope:
- Can be directly fixed to timber and steel framing.
- With absorbent wall claddings (e.g. timber, brick or fibre cement) or non-absorbent wall claddings (e.g. metal or plastic).
- Suitable for use in conjunction with 18mm minimum drained cavity.
- With masonry veneer in accordance with NZS 3604, NZBC Acceptable Solution E2/AS1.
- Situated in NZS3604 Building Wind Zones up to (and including) ‘Very High’ when used as a standalone flexible underlay, and “Extra High” when used as a flexible underlay over a rigid wall underlay.
- Is suitable to be used in conjunction with thermal breaks on steel framed buildings.
Refer to BRANZ Appraisal No 912 (2021) for full details.
General
- Fire retardant.
- Unaffected by LOSP or other solvent based treated timber. However, LOSP or other solvent based treated timber must have sufficient time for the solvent to flash off in a well ventilated area. Recommended minimum 7 days.
Limitations
- Must NOT be used as a roof underlay.
- Not suitable as an air barrier in unlined walls.
- Must NOT be exposed to the weather or UV for more than 42 days.
- Thermakraft 220 is NOT a vapour barrier.
Compliance
Thermakraft 220 has been appraised with the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1, with regards to building height and floor plan area. Thermakraft 220 has also been BRANZ Appraised for use on buildings subject to specific weathertightness design. Building designers are responsible for the building design and for the incorporation of Thermakraft 220 into their design in accordance with the declared properties and the instructions of Thermakraft Limited. Refer to BRANZ Appraisal No 912 (2021).
Flammability Index
Thermakraft Thermakraft 220 Wall 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.
Durability
Meets the Performance Requirements of NZBC Clauses B2, Durability (B2.3.1 (a) 50 years, B2.3.1 (b) 15 years and B2.3.2), E2 External Moisture (E2.3.2), and F2 Hazardous Building Materials F2.3.1, providing:
- It is not damaged.
- Installed in accordance with instruction guide.
- Is not left exposed for more than 60 days.
- Installed by or under guidance of Licensed Building Practitioners.
- Is compatible with cladding system used.*
* Note: specifiers and product user must test for wall cladding system compatibility with the underlay before installation.
Product Warranty
Standard Thermakraft warranty applies. Refer to Thermakraft Warranty Statement for further details. This item is available online here or call 0800 806 595.
Product Performance
| NZBC E2/AS1 Table 23 (NZ2295)Wall Underlay Properties | Absorbency | Vapour Resistance | pH of Extract | Shrinkage | Water Resistance | Air Resistance |
|---|---|---|---|---|---|---|
| Property Performance Requirement | ≥ 100gsm | ≤ 7MN.s/g | ≥ 5.5 and ≤ 8 | ≤ 0.5% | ≥ 20mm | ≥ 0.1 MN.s/m3 |
| Property Performance | Pass | Pass | Pass | Pass | Pass | CANNOT be used as an air barrier. |
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