5. Timber Cladding

5.1 There are several timber cladding systems that will provide a satisfactory outcome

5.2 There are various profiles – which have a slight impact on the shrinkage characteristics, but in reality the important part is the Width – a board that is 138mm wide x 19mm thick which is more likely to cup than a board that is 90mm wide x 19mm thick.

5.3 Fixing system - a “secret nailed/screwed” system relies on a single fixing towards the top of the board and a tongue and groove fixing to the base. Again, this may be acceptable for an 80mm board, but the wider the board, the less likely the fixing will restrain the board. A face fixed system of nails provides a more even distribution of restraint for the board and twice the fixings.

5.4 The finish is also very important – a dark finish attracts more heat and influences the performance of the board and a clear finished spotted gum wall is more likely to cup/warp/buckle than one that is painted white.

5.5 There are timber preservatives and timber treatments (sealers). Any finish needs to be applied in two (2) coats prior to installation, and all cut timber (ends, notches) need to be sealed during installation. A final coat is installed following installation.

5.6 Penetrations will allow water behind the cladding if not treated correctly – and rot the cladding and the substrate.

5.7 Flashing and Sealing around windows and doors is imperative to preventing water penetration behind the cladding.