Siniat Weather Defence™
Close the Building In and Keep Moving
One of the more frustrating things about external cladding systems is the programme impact. You can’t close the building in until the cladding is complete. And you can’t always get the cladding done quickly. So the internal trades wait. Weather holds everything up. Costs mount.
Siniat Weather Defence™ changes that dynamic. It’s a 13 mm rigid air barrier board that gets fixed to the structural frame behind the external cladding system, making the building weathertight without the cladding in place. Internal trades can start. The programme moves forward. The cladding goes on afterwards. It’s a straightforward idea with a real, measurable impact on how a project runs.
What Weather Defence™ Is - and What It Isn't
Weather Defence™ is a rigid air barrier board, not an external lining that gets left exposed, not a standard internal plasterboard, and not a vapour barrier. It’s a product designed specifically for use in the wall cavity of rainscreen and ventilated facade systems, where it performs three functions: weatherproofing the structure while external cladding is installed, providing structural racking resistance to the frame, and offering fire and thermal performance within the wall assembly.
Understanding where it sits in the assembly is important for correct specification. Weather Defence™ is installed on the outside of the structural frame, behind the external cladding, ahead of the Nvelope subframe (if used) and the cladding panels. It is not a replacement for the external cladding system.
Technical Specifications
Thickness
13mm
Material
Gypsum-core rigid board, similar base to standard plasterboard
Fire classification
Non-combustible under NCC, suitable for Type A and Type B external walls
Fire resistance level
Class 4 vapour-permeable, suitable across most Australian climate zones
Bushfire suitability
Can be used to wrap the full building envelope as ember-attack protection in BAL-rated zones
Frame compatibility
Timber- and steel-framed construction, commercial and residential
Standard size
1200mm × 2400mm (standard sheet)
Programme Benefits
The programme case for Weather Defence™ is simple and measurable. Once the board is fixed to the frame, the building is weathertight. That means:
Internal trades can start earlier
Plumbing, electrical and internal linings can begin before external cladding is complete; trades don't sit waiting for the building to be enclosed.
Weather holds are reduced
Rain and wind don't penetrate the structure once Weather Defence™ is in place. Work inside continues regardless of external conditions.
Cladding can follow at its own pace
Complex or long-lead-time cladding systems can be installed without holding up the rest of the programme; the external envelope is already protected.
Programme savings translate to cost savings
Reduced delays, fewer weather holds and concurrent trade activity all reduce the cost of carrying a project from frame completion to handover.
Featured Projects with Siniat Weather Defence™
Frequently Asked Questions
What does Siniat Weather Defence™ actually do in a wall assembly?
Siniat Weather Defence™ is a 13mm rigid air barrier board fixed to the outside of the structural frame. It makes the building weathertight before external cladding is installed, which allows internal trades to proceed while cladding work continues on the exterior. It also provides racking resistance and fire performance within the wall assembly. It is not a standalone cladding product; it sits behind the external cladding in a rainscreen or ventilated facade system.
Is Siniat Weather Defence™ non-combustible?
Yes. Weather Defence™ has a gypsum core and is classified as non-combustible under the NCC, making it suitable for use in Type A and Type B external wall construction, including high-rise commercial and multi-residential buildings.
Is Weather Defence™ suitable for use in bushfire-prone areas?
Yes. Siniat Weather Defence™ can be used to wrap the full external building envelope as protection against ember attack in bushfire attack level (BAL)-rated zones. It is vapour-permeable (Class 4), making it suitable across most Australian climate zones without moisture management concerns.