Ventilated Wood Facades: The Durability Secret Few Notice
Many wood facades start warping and rotting two or three years after installation, not because of bad wood, but because of a missing air gap behind the cladding.
Installing Timber Cladding: Battens, Screws and Fixings That Last
Timber cladding fails more often from its battens, screws and gaps than from the wood itself. Here are the practical installation points, from the substructure to stainless screws.
Most timber facades that turn black, crack or cup early do not suffer from bad wood; they suffer from poor timber cladding installation. Screws that rust, boards fixed tight to the wall with no gaps, or an unplanned substructure all show up within a summer or two. This article walks through the right sequence, from the wall to the last screw.
The substructure: cladding sits on battens, not on the wall
Cladding boards are not screwed directly to the wall. First, battens (treated timber or galvanized metal profiles) go on the wall, and the boards are fixed to them. This layer does three jobs: it evens out an uneven wall, carries the load of the facade, and creates an air gap behind the boards so moisture can escape. German guidance typically asks for at least 2 cm here; we explained why in our article on ventilated wood facades.
- Battens run perpendicular to the boards: for horizontal cladding, battens are vertical so water drains down behind. For vertical cladding, a double layer (horizontal over vertical) is needed so the air path is not blocked.
- Batten spacing: European guides typically give around 40 to 60 cm, depending on board thickness; thinner boards need closer spacing.
- Keep the top and bottom open: air enters at the bottom and leaves at the top, behind an insect mesh, not sealed with mortar or caulk.
Screws and nails: the fixing matters more than the species
Woods such as oak, and thermowood from many species, react with ordinary iron and leave black stains or dark streaks around the screw that will not wash off. That is why only stainless steel screws belong on a facade; cheap galvanized screws lose their coating over time and cause the same stains. A few installation rules:
- Pre-drill, especially near board ends; thermowood is more brittle than untreated timber and splits at the ends without a pilot hole.
- Screw heads flush, not sunk deep; a recess is a place for water to sit.
- A gap of a few millimeters between boards, so each board has room to move through summer and winter.
- Hidden clips look cleaner, but not all of them suit vertical or wind-exposed facades; check the manufacturer's instructions.
Board ends, corners and the base of the facade
The end of a board (the cross-section of the fibers) absorbs many times more water than its face. Every cut end should be sealed with paint or end-grain oil right there on site. The bottom of the cladding should stop at least a few centimeters above the ground or balcony floor so splashing water does not reach it. Close corners with a corner profile or an overlapping joint, not with silicone that comes away after a few years.
Screws and air keep a timber facade alive, not the wood alone.
In sunny climates like central Iran, strong sun and big swings between day and night temperatures make boards move more, so gaps and pilot holes matter even more there than in damp Europe. To choose a board layout, see types of wood facade patterns, and for after installation, see our wood facade maintenance schedule.
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