Across Europe is very common to find bridges build in sawn and glue-laminated wood. Most of these bridges used softwood wood species such as: fir, spruce, larch and pine. In Spain wooden bridges, became more and more popular since nineties, when sawn and glue-laminated wood were utilized for building exterior wooden structures in overall Spain. This material, sawn and glue-laminated wood, are made in a lot of cases of fir (Abies alba) and spruce (Picea abies), generally from central and northern European origin and production without a correct treatment to improve their low natural durability because their use is previewed in use classes 1-2 according to the standard EN 335: 2013. The diversity of wood species, preservative treatments and designs, combined with the variability of environmental conditions (different climatic zones and exposure to weathering), has led to the emergence of pathological processes associated primarily with fungal decay (wood destroying fungi) and wood destroying insects in lesser extent. In some wooden bridges, the magnitude and extent of the damage due to early decay was such that it has reduced the cross section and strength of wooden components, directly affecting the safety of these structures. This paper, with a case situation of early decay in spruce bridge located in North-West Spain, tries to summarize the situation of these exterior structures built in the nineties. In some cases, damages had appeared before ten years of service life. As it will be shown, in this warm and wet area of Spain, wooden parts or joints that create water traps, including the structural elements, present such a destruction level that most of the times the substitution of the bridge is mandatory. So the aims of the study of this case are to understand the cause of early severe decay. It is important to remark that the definition of a proper approach to degradation of spruce bridges, need different competences such as architects, civil engineers, wood technologists, biologists, etc. The case of study has always been analyzed according to the occurrence of decay or failure, but this fact does not mean that all Spanish spruce bridges have this kind of problems, or that are not well designed.

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