On the outside of the non-loadbearing nib wall you can see a small display of James Hardie’s ComTex façade system, which has been designed to deliver a render finish to light weight structures. Note that the yellow façade panel here performs as a pre-primed and textured base, ready for the addition of a textured acrylic coat. When selecting a colour finish to fibre cement-based façade panels it is important to consider the light reflectance value of the colour and exposure level of the panel, as darker finishes will attract more heat in high exposure locations and may risk damaging the facade as it expands. This product requires finishing with a colour attracting a light reflectance value of at least 40, which roughly correlates to light pastel or cream shades.   

A common theme amongst all the façade systems shown on this structure, the ComTex system effectively acts as a pressure-equalised rainscreen, featuring a ventilated cavity between the visual façade and the vapour permeable membrane behind. This gap allows for the natural egress of any moisture that enters the system, minimising the risk of water damage.

The vapour permeable membrane utilised behind this rainscreen has been supplied by TBA Firefly, and is classed as both vapour permeable and non-combustible. It is important to utilise a vapour permeable membrane in timber facades, as this allows moisture to permeate out of the timber system while preventing moisture from entering. While there are a number of membranes marketed as “breather membranes” it is important that any membrane used in this function is highly permeable, and supports a rate of vapour transmission of at least 4 µg/N.s. (4 micrograms per newton second).

Behind this vapour permeable membrane, you can see two layers of 13mm fire wet stop plasterboard supplied by USG Boral. Even though this wall is non-loadbearing, it is a requirement for all combustible elements utilised within a façade to be fire protected to a specified FRL.