Does the question of cladding thickness arise only for wooden cladding?

No, thickness is an important criterion for every type of cladding , but it has different implications depending on the material chosen. For wooden cladding , thickness plays a structural, decorative and partly insulating role. It must be matched to the width of the cladding board and to the type of installation so as to avoid distortion. For composite wood cladding , the thickness is often standardised by the manufacturers. Since composite wood is often reinforced (fibre, resin and so on), a lower thickness can be enough while keeping good rigidity and durability and an elegant appearance. There is therefore less need to adjust it case by case. Composite wood is an excellent alternative to wooden cladding. For PVC cladding , the thickness is also set by the manufacturer. PVC is light but less rigid: it often relies on a well-designed load-bearing structure to compensate. The thickness is therefore important, but it is generally not for you to choose: it is imposed by the form of the product.

Does the thickness of the cladding reinforce the effectiveness of the breather membrane?

Not directly. The thickness of the cladding does not reinforce the breather membrane itself, but it protects the façade as a whole better, which can extend the effectiveness of the breather membrane over time.

What batten thickness for cladding?

The thickness of the battens depends on the type of cladding installation and on the presence of insulation. In the case of cladding without external insulation, battens 27 to 40 mm thick are generally enough to create the compulsory ventilated air gap. When the cladding is laid over external thermal insulation (ITE) , the thickness of the battens must make up for the thickness of the insulation. Battens or rafters of 60 to 100 mm are then used, or even more, or a secondary framework on rails. In every case, an air gap of at least 20 mm must be guaranteed between the cladding and the wall or the insulation, so as to ensure natural ventilation and avoid moisture problems. Finally, when cladding is laid vertically, a double crossed framework (battens + counter-battens) is often needed to fix the boards correctly, which also affects the total thickness to allow for.

What thickness for wooden cladding? Complete guide

The thickness of wooden cladding plays a key role in the durability, the stability, the appearance and the strength of a façade. If it is too thin, the cladding risks distorting; too thick, it needlessly weighs down the structure with no significant thermal benefit.

Choosing the right thickness therefore means finding the right balance between performance, technical constraints and budget for the façade of your house or building. Discover how to choose the right thickness for your project!

In brief: what to remember

The minimum thickness of wooden cladding is generally between 15 mm and 18 mm. It depends on the space between the battens supporting the cladding: 15 mm for a centre-to-centre spacing of 40 cm or more, 18 mm for a spacing of 65 cm or less.
For exposed or tall façades, favour a thickness of at least 20 to 21 mm.
Some types of installation (open-jointed, wide boards) sometimes require a reinforced thickness (up to 27 mm).
The thickness of the cladding does not provide the thermal insulation of your façade: the cladding must be combined with a high-performing insulating material.

Use of the wooden cladding	Recommended thickness
Lightweight / interior cladding	12 mm
Standard external cladding	15 to 18 mm
Tall cladding	20 to 21 mm
Cladding exposed to the weather	20 to 21 mm
Open-jointed cladding	21 to 27 mm

What criteria determine the thickness needed for wooden cladding?

Several factors influence the choice of thickness for wooden cladding: the mechanical constraints on the surface, the type of installation, appearance, environment and also the type of wood used.

Here are the main criteria to consider:

Exposure to the weather

The more your façade is exposed to wind, rain or temperature variations, the thicker the wooden cladding will need to be to last over time. A minimum of 20 to 21 mm is recommended in this case, or even more for open-jointed cladding.

The height of the façade

A tall façade (more than 3 metres high) is subject to greater mechanical stresses, for example the effect of the wind. You should therefore opt for a thickness of 20 mm minimum, or even 22 mm if the space between the battens of the framework is large.

The spacing of the supports

The centre-to-centre spacing is the distance between the battens or uprights that support the wooden cladding. The greater this distance, the thicker the cladding must be to avoid sagging.

Spacing	Recommended minimum thickness
≤ 40 cm	15 mm
40 to 65 cm	18 mm
> 65 cm or high stress	20 mm and above

The type of installation: open-jointed, wide boards and so on

Some ways of laying wooden cladding impose greater mechanical constraints, which requires a greater thickness to guarantee the stability and the durability of the cladding.

Open-jointed: since the boards are spaced apart, they must be properly rigid to avoid visual or mechanical distortion. Recommended thickness: 21 to 27 mm.
Wide boards (more than 120 mm wide): in the case of a very wide board, the thickness of the cladding must be increased to limit the risk of twisting or sagging. Make sure that the visible part of the board (that is to say the width on show once laid, excluding the overlap) does not exceed 7.5 times its thickness — or up to 10 times for very stable woods such as red cedar or larch — so as to avoid the risk of distortion (twisting, sagging).

The wood species

Every wood species has its own mechanical properties: a dense wood such as oak needs less thickness than a soft wood such as pine. Some species such as red cedar allow thinner sections thanks to their natural stability. Your manufacturer will be able to advise you on the thicknesses suited to the different species.

Appearance

The thickness of the cladding directly influences the visual result of the façade. A board of good width and greater thickness often gives an impression of solidity, character and nobility, especially in vertical installations or contemporary styles.

For volume effects or open-jointed cladding, a greater thickness (21 mm or more) makes it possible to accentuate the play of shadow between the boards. Thinner boards, conversely, give a more discreet or traditional look.

Adapt the thickness to the overall architecture of the house, to the type of installation (horizontal, vertical, diagonal) and to the style you are looking for (modern, rustic, minimalist and so on).

Special cases: interior cladding, vertical installation, cladding over insulation

For decorative interior cladding or a lightweight-looking facing with no climatic constraints, a thickness of 12 mm is generally sufficient. This type of cladding is above all decorative, installed in a protected environment, with no need for particular resistance to the weather or to temperature variations, purely for decoration.

In the case of a vertical or diagonal installation, the boards are more exposed to water running down them. This configuration can encourage infiltration or standing moisture if the wood is not robust enough. It is therefore recommended that you choose a thickness of between 18 and 21 mm so as to ensure it holds up well over time.

When the cladding is laid over external thermal insulation (ITE), it plays a role of mechanical protection as well as being decorative. It has to withstand the stresses linked to wind, to the fixings and to the movements of the façade. Here too, a thickness of 18 to 21 mm is to be favoured so as to guarantee stability and durability.

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What cladding thickness for good insulation?

The thickness of wooden cladding slightly influences thermal and acoustic insulation, but it remains secondary to the insulating material placed behind it. Wood is a natural insulating material, but its performance alone is not enough to meet the requirements of effective external insulation.

Thicker cladding (18 to 21 mm) offers better density, limiting heat transfer and noise. Nevertheless, it is the insulating material (wood fibre, polystyrene, polyurethane and so on) laid behind the cladding that plays the main role. The cladding protects the insulation, but it does not replace it.

The thickness of the cladding should above all be chosen to optimise its mechanical and decorative function. A thickness of 15 to 21 mm is recommended depending on the case, but it does not replace a high-performing insulating material.

Cladding alone (without insulation): 15 to 18 mm, limited insulation.
Cladding with external insulation : 18 to 21 mm + 10 to 20 cm of insulation, for optimal thermal performance.

Good practice for choosing the thickness of your wooden cladding

Follow the recommendations of the manufacturer and of DTU 41.2 (Document Technique Unifié, the standard that governs the rules for installing wooden cladding in France).
Choose the thickness suited to the use (see the summary table above).
Adapt the thickness to the width of the boards so as to avoid distortion.
Do not try to make up for average insulation with an excessive thickness of wood; it is better to put insulation in place under the cladding.