Partner responsible: Galician Forest Industry Agency (XERA – CIS Madeira), Spain.

Description: The presence of subterranean termites is frequent in southern Europe and, however, the legislation is different (or non-existent) in the different affected countries such as Spain, France and Portugal. Facing the doubts that may arise in certain situations, it is proposed to review the main existing solutions to improve durability against subterranean termites and, in particular, their application to cross-laminated timber (CLT) panels.

Among these solutions, it is worth mentioning an adequate constructive design, the provision of anti-termite barriers, the application of chemical treatments, etc.

The constructive design includes, mainly, measures aimed at avoiding humidity infiltration into the panels, thus limiting the possibility of attack by subterranean termites. In high-rise buildings, these measures can contemplate that the basements and first floors of the building are made of other materials and that the starting of the wood structure begins in the upper floors.

Other good practices include the support of the panels on raised walls from the ground, the use of sleepers made of a material with greater durability (natural or conferred), the use of end grain sealants, damp proof membranes, etc.
It may also be important to provide visibility and accessibility to the structure in order to detect an attack in its early stages.

Physical or physical/chemical termite barriers are a common and effective solution that can be installed at the interface between the ground and the building foundations or in a partial way on the support of the CLT panels. Both types of barriers prevent termites from crossing them.

Chemical treatments, in the case of CLT panels, usually consist of a surface treatment and their greater or lesser effectiveness is related to the type of product and the species of timber used.

In this sense, along with the review of existing solutions, some tests will also be carried out to compare the impregnability of radiata pine and Norwegian spruce, two species commonly used in the production of CLT.