Certification in the wood preservation sector

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Treated timber for claddings

Construction cladding used outdoors and simple to install.

They are made of strips of timber on appropriate supports (cleats, battens or a frame). Related products are, for example, clapboards and planks of various sizes.

Logo performance des bois certifiés CTB-B+


The strips and battens treated according to CTB-B+ specifications are reliable in terms of use and expected service life.
They are suitable for the uses described in the DTU [unified technical document] 41.2 that specifies, for example :
• use classes 3.1 to 4 according to the usage situations (exposure)
• expected durability
• these products are subject to CE marking in compliance with with standard EN14 915

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CTB-B+ treated wood ensures the service life of the cladding inservice. To ensure its durability, the
installation rules for these products laid down in DTU 41.2 should be observed. According to treatment procedures
and type of product used, an additional finish may be required.

Logo entretien des bois certifiés CTB-B+


Timber cladding weathers with time and maintains its durability afforded by the CTB-B+ treatment. Its aesthetic appearance is maintained by cleaning using a brush and/or water jet (high pressure prohibited) or by the application of decorating products.

Universal use classes, specifications of different treatments :

Before choosing the timber species, please refer to the use class. Identical in every country, the uses classes define the situation of the timber in a particular structure. They do not, however, attest to its suitability for use. For the same use class, the treatment requirements may vary from country to country. Each species has its own characteristics in terms of natural durability (before treatment) and impregnability (capacity to retain the product). The allocation of a species to a use class determines how the timber should be treated. Its effectiveness depends on the selection of the timber, the quality and quantity of the product used and how the process is managed and controlled.
tableau des classes d'emploi du bois 3.1 3.2 et 4
schéma des différentes classes d'emploi du bois pour les bardages

Fiche technique pour bien comprendre les classes d'emploi des bois



To help professionals make the right choices, holders of the CTB-B+ Mark publish a brochure entitled
« Fully understanding the classes of use ».

Download Fully understanding the classes of use