The look and feel of rendered facades is familiar throughout Australia and new technologies have given rise to various synthetic renders, but have you considered if render is ever required by the Deemed-to-Satisfy (DTS) Provisions of the NCC to be non-combustible?
Further information is available in the Advisory Note: Fire performance of external walls and cladding, but here is some initial guidance to help you on your way.
NCC requirements for external walls required to be non-combustible
For a building of Type A or B construction, C1.9(a)(i) specifies that elements of external walls, including their components, must be non-combustible. Components of external walls include:
- façade covering (e.g. render and external cladding)
What does non-combustible mean?
In the case of a material like render, ‘non-combustible’ means the material is capable of not being found combustible having been tested in accordance with AS 1530.1 — Combustibility Tests for Materials.
Can I use render on an external wall required to be non-combustible?
Render when used as part of a DTS Solution for an external wall of a Type A or Type B building must be non-combustible.
Render is normally a component of the external wall and is not provided with a concession or exemption in C1.9(d) or C1.9(e).
For situations where render is considered an ancillary element to the external wall, it is only permitted as a DTS Solution if it is non-combustible under C1.14(a). It is important to note that render is different to paints and lacquers, which are permitted ancillary elements under C1.14(l).
Textured paint, albeit not a flat paint finish, is commonly used as a final layer or coating to a wall. C1.14(l) does not specify the types of paint that may or may not be permitted. As such, textured paint is a permitted ancillary element.
Regardless of whether render is part of an external wall or an ancillary element to buildings of Type A or Type B construction, where part of a DTS Solution, the render must be non-combustible.