Wood cladding dresses a facade with warmth and character. But behind the aesthetic aspect lies a technical work, subject to precise rules. Poorly installed, the wood deforms, retains water, and eventually rots. Properly installed, it protects the house for decades. Here is what you need to know before getting started, from the choice of wood species to the ventilation of the facade.
A coating regulated by a standard
| Element | Recommendation | Lifespan | Impact |
|---|---|---|---|
| Wood species | Douglas / Red Cedar | 20 to 40 years | High |
| Air gap | 20 to 40 mm | – | Essential |
| Rain barrier | Mandatory | 10 to 30 years | Moisture protection |
| Fasteners | Stainless steel A2/A4 | Long term | Anti-corrosion |
| Maintenance | Every 5 to 10 years | – | Durability |
In France, the installation of wood cladding is not done randomly. It complies with DTU 41.2, the technical reference document for exterior wood claddings.
This standard sets everything that matters: the choice of species, facade ventilation, fasteners, and the distances to respect. Its 2015 revision even included open-joint installation and concrete or masonry supports. Before starting the work, reviewing the DTU tolerances and rules for wood cladding will save you from costly mistakes. Compliance with these requirements also conditions the ten-year warranty if installed by a professional. Needless to say, it’s best to know them from the design stage.
Choosing the right wood species and use class
Everything starts with the wood itself. An unsuitable species for its exposure will not last, regardless of installation quality.
The DTU works with use classes. A sheltered facade only requires class 3.1, while severe exposure, such as seaside or mountain, demands class 3.2 or 4. Some species are naturally resistant, like larch, Douglas fir, red cedar, or chestnut. Other woods are made durable by pressure treatment or thermal treatment. For finishing, you have the choice: let the wood gray naturally, apply a saturator that nourishes the fiber, or opt for a more covering stain.
Golden rules for installation
The durability of cladding mainly depends on the implementation. Some principles always come back.
- A rain barrier protects the wall from infiltration while allowing the wall to breathe.
- A ventilated air gap of at least 20 mm, with a low inlet and a high outlet, ensures drying of the wood and evacuates moisture.
- A frame of battens treated class 2, spaced 40 to 65 cm apart, serves as support for the boards.
- A ground clearance of 20 cm prevents water rise and mud splashes.
- A wood moisture content below 19% at the time of installation, after unpacking the boards 24 to 48 hours before.
Fixings deserve special attention. The DTU requires stainless steel, A2 for a standard environment and A4 near the coast. The heads must be flush with the surface, neither too recessed nor protruding. For narrow boards, a single hidden fixing is sufficient, whereas wider boards require two.
Pitfalls to avoid
Most defects come from shortcuts taken during installation. Three mistakes are common.
- Blocking the air gap or installing a discontinuous rain barrier. Moisture remains trapped and the framework rots.
- Using standard fixings. Untreated nails rust and stain the wood, especially with acidic species.
- Installing wood that is too wet. As it dries on the facade, the boards shrink and warp.
A final common oversight concerns administrative matters. Changing the exterior appearance of a house often requires a prior declaration of works at the town hall. It is better to check local planning rules before buying any cladding.
🌍 Did you know?
A well-ventilated wood cladding can last up to twice as long as a poorly installed cladding, even with the same type of wood.
Maintaining your cladding over time
Wood is alive, and its appearance evolves. Left raw, it takes on a silvery gray hue over the seasons, without its strength suffering.
If you want to keep the original color, a saturator is generally applied every two to three years, depending on exposure. A gentle cleaning beforehand is sufficient in most cases. Avoid high-pressure washers, which damage the wood fibers and open the way to cracks. With these simple steps and proper installation, a wood cladding withstands the years without weakening and retains all its charm.
To go further, I recommend choosing your cladding to compare materials. You can also see facade waterproofing to prevent infiltration. And finally exterior coatings to complete your project.
Frequently asked questions
u003cstrongu003eQuelle est la garde au sol minimale pour un bardage bois ?u003c/strongu003e
Le DTU 41.2 recommande une distance d’au moins 20 cm entre le bas du bardage et le sol, afin d’éviter les remontées d’humidité et les projections.
u003cstrongu003eLa lame d’air ventilée est-elle obligatoire ?u003c/strongu003e
Oui. Une lame d’air d’au moins 20 mm, ventilée en partie basse et haute, est indispensable pour évacuer l’humidité et garantir la durabilité de la façade.
u003cstrongu003eQuel taux d’humidité pour les lames au moment de la pose ?u003c/strongu003e
Le bois ne doit pas dépasser 19 % d’humidité. Il est conseillé de déballer les lames 24 à 48 heures avant la pose et de les stocker en pile aérée.
To go further
