Special cases of frameworks
Timber-frame house - Materials for wood construction

In the most common cases, an interior structure is classified in risk class 1 or even 2, if transport, storage or the building site present a risk of temporary wetting of the wood. This is not the case when the structure is located in a humid atmosphere. Depending on the extent of the risk of wetting and the position of the timber in the structure, it may be necessary to move up to class 3 or 4, in which case the treatment or choice of species must be adapted accordingly. Table 7 clarifies these points and indicates the corresponding risk class for each exposure condition.