Bevel-back, shiplap and rusticated timber weatherboard installation considerations

The Team at Palliside 04 September 2018

Exterior Cladding Cladding Materials

Bevel-back timber weatherboard
These classic timber weatherboard profiles have a well-earned reputation for weathertightness and durability—but, like any cladding, only if they are installed properly. 

Ensure your cladding is installed correctly with our profile-by-profile overview of common mistakes below.

 


 

Bevel-back

Bevel-back is a traditional timber weatherboard profile in New Zealand, and remains extremely popular today. Its most notable feature, the presence of a void between boards, enables it to have a high level of drainage and drying capacity, ensuring a robust defence against moisture, even if used in a direct fix application.

Enough space must be left between the boards to allow for changes in size during temperature adjustments—a matter of just a few millimetres could be enough for expansion to result in board cracking or cupping.

The same theory applies to “doublenailing”, or the act of driving a fixing nail through the top of one bevel-back as well as the bottom of a connecting board. This results in less flexibility for the boards, and can result in damage during thermal expansion.

This is why many tradesmen utilise materials that don’t suffer from thermal expansion and cladding systems that have been engineered to allow for expansion and contraction–such as uPVC and aluminium


See how timber performs against other weatherboard cladding materials



 

Rusticated

If rusticated timber weatherboards are direct fixed to framing, they lack the void of bevel-backs, and thus have lower natural air flow. This is combined with a higher contact area with the underlay, exacerbating the existing lower level of drainage and drying capacity.

If installed incorrectly, this can lead to problems with moisture damage to the weatherboards, depending on the material and its water permeability. To avoid this, contractors must be careful to only direct-fix these boards to buildings with a risk value of 6 or lower. Any higher, and they must be installed over a 20mm cavity.

Rusticated timber weatherboards (or any material that suffers from thermal expansion) must also have the additional consideration of expansion during hot weather and shrinkage during cold weather.

 


 

Shiplap

Like rusticated timber weatherboards, shiplap-style timber weatherboards if direct fixed to framing lack the void of bevel-backs, resulting in less natural air flow. This is combined with a higher contact area with the underlay, exacerbating the existing lower level of drainage and drying capacity.



 

What about Palliside?

Palliside weatherboards are available in bevel-back and rusticated profiles. In both cases, they are designed to perform well in either direct fix or drained cavity applications.

Unlike timber weatherboards, our solid uPVC weatherboards are manufactured, not harvested. Palliside’s unique prefabricated profile fits together to hide fixings without the need for doublenailing and also prevents moisture egress. The system is engineered to allow for thermal expansion.



For more information about what cladding to use for your home or project, download our free comparison matrix below.

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