How to choose the best curved timber option for your application

Curved or wave-shaped forms in architecture derive their inspiration from the beauty of nature and its natural fluidity. Integrating complex timber curvatures can be a challenge for any designer but also a brilliant way to create a spectacular sculpted surface. The properties of wood and its susceptibility to movement mean that designers need to consider the right manufacturing option to achieve their curved timber design.

This article outlines how we have commercialised curved timber and which of our two available options would be best suited to your project.

Our curving options

Creating curved timber forms is a complex process, and often difficult to effectively achieve on a commercial scale. Factors that need consideration, depending on the intended application are: 

• the timber species and density
• the radius of the required curve,
• the method of fixing 

We offer two options for achieving curved timber – Steam bending and Kerfing that utilise our Click-on Batten System for walls and ceilings.

Steam bending

An extension of the traditional art of steam bending timber, our bending process takes the same principles and applies them on a much larger scale. Timber battens are heated to a high temperature under strict moisture conditions to make them malleable, then curved using a former to hold the timber in place until it cools and dries. When the wood has completely cooled, the piece will remain in the shape of the desired template and is supplied to site ready to install.

Pros		Cons
Perfect for seamless transitions between walls and ceilings Provides organic, uninterrupted curves Simplifies installation of complicated curved forms Sculptform supply and install ensures fast and accurate installation		Not practical for applications requiring a range of different radii – is better suited to applications requiring lots of the same curve More expensive than kerfed timber Only a select range of species and coatings available

 

Kerfing

Kerfing is the simplest way to curve timber and involves cutting hundreds of small notches into the back of the timber batten to allow it to bend or curve. These battens are supplied to site in straight, but flexible lengths, to be formed or flexed around curves on-site.

Pros		Cons
Cost effective curved timber solution Can be used for applications requiring a gradually increasing curve Can but adjusted on site to fit required radius Broad range of and species and coatings available		Limited number of profiles available Kerf lines can disrupt the aesthetic Form is required on site to establish curve More mounting track required to compensate for the reduced rigidity of the battens

 

Factors to consider

There are a few key factors which must be considered when choosing the right curved timber solution for your application.

1. The required radius
   While there are overlaps depending on project-specific conditions, a general rule to follow is that radii of less than 1.5 metres are better achieved with steam bending, and radii of over 1.5 metres are suited to our kerfing option.
2. Consistent or variable curves
   For projects which have a large number of battens curved to the same radius, steam bending timber is a perfect option. The manufacturing process uses formers which allow us to create a large number of battens at the same radius quickly. In comparison, applications which have gradually changing radii are best suited to our kerfing option. Kerfed battens are provided to site straight but flexible due to the kerfing, which allows them to be fit on site to the required curve.
3. Aesthetic differences
   Steam bending can sometimes create some minor compression marks on the timber. These marks are largely unavoidable due to the natural properties of timber, however can be minimised through a larger radius bend or reducing the depth of the batten. When the battens are kerf cut the notches can sometimes be seen from the side. These can be combatted by having a smaller gap between the battens (eg. 5-10mm) or you can use a custom tapered side batten to minimise the effect
4. Cost difference
   The process of creating curved timber battens does add to the cost due to the extra labour involved, however value management is possible with the options provided by the Click-on Battens system. By changing the gap between the battens, coatings or even timber species, there is an option available for most budgets.When compared, kerfing is the more cost-effective of the two options, while the higher cost of steam bending offers a greater range of radius options and a more seamless look.

Steam bending	VS	Kerfing
Radii < 1.5 mtr Fixed radii  Variable batten spacing Limited timber species Length limitations < 2 mtrs Strong, stiffer batten Forming tool investment		Radii > 1.5 mtr Variable Radii Close batten spacing (< 10mm) More species options Length only dictated by species availability Flexible batten Kerfing process – CNC

Other options for curving timber

Have any questions?

Our clients are at the heart of every project. It’s our job to deliver on the big picture and the smallest detail. We’re your proactive design partner – we’ll listen to what you really need and work with you to make sure the job gets done right.

We would love to hear about your next curved timber project!

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