Sustainable wooden retaining wall.

Choosing the wood and designing the retaining wall structure

Choosing the right wood and designing the structure are fundamental steps in ensuring the durability and stability of your retaining wall. Careful planning and careful material selection are essential for the success of your project.

Selecting wood species for retaining walls

Several types of wood are suitable for retaining wall construction, each with specific properties in terms of durability, strength, and cost. Oak, with its excellent natural durability and high strength, is a preferred but expensive choice. Chestnut, known for its rot resistance, offers a good compromise between durability and price. Larch, on the other hand, is valued for its strength and relatively affordable cost, but requires treatment for optimal durability. For less naturally durable woods (such as pine), a Class IV autoclave treatment is essential to ensure protection against moisture and wood-boring insects. The use of FSC or PEFC-certified wood is recommended to ensure responsible forest management. The choice of wood section will depend on the height of the wall and the pressure of the ground: for a 1.5-meter-high wall, 15x15 cm sections are generally recommended, while for a 2.5-meter wall, 20x20 cm sections or more will be required. A preliminary geotechnical study is recommended to determine the optimal dimensions.

• Oak: Exceptional durability (estimated lifespan of over 50 years without treatment), high mechanical resistance, high cost.

• Chestnut: Good natural durability (around 30 years without treatment), average resistance, average cost.

• Larch: Good natural resistance (20-30 years depending on treatment), average cost, requires treatment for better durability.

• Class IV autoclave-treated pine: Durability increased by treatment (approximately 20 years), average resistance, affordable cost.