The GIB Weatherline® rigid air barrier systems are an integral part of an external wall system. This has led to involvement in more discussions about external cladding systems and we are often asked when claddings are required to be non-combustible. Although claddings are outside the scope of our GIB® plasterboard systems, they are relevant to certain boundary wall applications. The requirements of NZBC Acceptable Solution C/AS1 Clause 5.3.1 ‘External wall cladding materials’ are summarised below. When in doubt, or for specific material properties, contact your design team and cladding supplier. 

Combustibility restrictions apply when walls are sufficiently close to a property boundary. This is to ensure that there is low risk of ignition and spread in case of a fire next door. 

Cladding restrictions apply when, 

• the distance to the relevant boundary is less than 1.0 metre, measured from the boundary to the cladding face, or 
• the angle between the wall and the boundary is less than 90°, or 
• the building height is greater than 10 metres, measured from the internal ground floor level to the building apex.  

Cladding restrictions do not apply when the building has sprinklers. 

How is this applied to some common intertenancy boundary walls? 

Figure 1 – Cladding is 90° to the boundary. No cladding restrictions apply. 

Figure 2 – All cladding is equal or greater than 90° to the boundary, and not facing adjacent property. No cladding restrictions apply. 

Figure 3 – Cladding is part of Unit B wall and is less than 1.0 metre from the boundary. Cladding restrictions apply. 

Figure 4 – Unit A cladding is less than 90° to the boundary. Cladding restrictions apply within 1.0 metre measured perpendicular to the boundary.  

Unit B cladding is not facing the boundary at less than 90°. No cladding restriction apply.  

Figure 5 – Cladding is part of Unit B and not facing adjacent property. No restrictions apply.  

Figure 6 – Cladding is part of Unit A and within 1.0 metre from the boundary. Cladding restrictions apply. 

As all our GIB® Fire Rated plasterboard systems, including GIB Weatherline®, are tested with plasterboard only (no cladding), this means our systems are not reliant on cladding properties in order to achieve the published FRR. 

Any questions call the GIB® Helpline 0800 100 442