Siberian Larch (Decking Boards)

Siberian larch is a coniferous species with high density and natural resin content, used outdoors primarily for decking boards under pergolas and around saunas and hot tubs. Slow growth in a cold climate produces a dense, finely structured wood grain with higher mechanical strength than common Central European conifers. High resin content acts as a natural barrier against moisture, rot, and wood-boring insects without the need for chemical impregnation. Left untreated, the wood gradually develops a silver-grey tone typical of long-exposed exterior timber. In exterior wellness assemblies, larch is often combined with an aluminium pergola, which forms the load-bearing and shading structure above the deck.

Advantages of Siberian larch

• Natural resistance without impregnation: High resin content protects the wood against moisture and biological damage without chemical treatment.
• High mechanical strength: Slow growth in a cold climate produces a denser wood structure than fast-growing species.
• Good balance of cost and durability: Compared with tropical hardwoods, it offers comparable durability at a lower cost.
• Natural greying without loss of function: The colour change is only superficial and does not affect the board’s mechanical properties.

Decking boards: larch, ThermoWood and composite

Around a sauna and a hot tub the terrace is permanently exposed to water, and in winter to frost as well. When choosing a decking board for this setting, three materials are most often compared.

Building decking around a tub and a sauna

With decking that runs around a bathing tub or a sauna, two things are worth thinking about beyond an ordinary terrace. The first is access to the equipment – the boards above the pipework and the pump should be removable, otherwise the whole area has to be taken up for servicing. The second is getting water off a surface that is walked on with wet feet; adequate gaps between the boards and a fall away from the structure keep water from standing at the foot of the sauna.

Related terms: Thermo Wood, Drainage system, Bioclimatic louvres, Powder coating.