Exposed timber with conventional coatings only achieves Group 3 status. However, it's possible that a case can be made for CLT 'massive construction' combined with fire retardant treatment to achieve Group 2 status via a Performance Solution. More detailed advice on using this pathway is contained in our Technical Design Guide #17 titled Fire Safe Design of Timber Structures - Compliance with the NCC. A copy can be downloaded free of charge from our website via this link https://www.woodsolutions.com.au/publications.

The Table below from NCC 2019 Building Code of Australia will explain the requirements for the Fire Resistance Level (FRL) of various building elements in Type C construction. If the external wall is 3 m or more from a fire source feature no special fire resistance is required. If between 1.5 to less than 3 m, the external wall must have an FRL of 60/60/60 (see table below). The FRL is measured from the outside, so timber is acceptable as long as the outer skin has an FRL of 60/60/60.