The circumstances which the ready glue joint has to endure, have to be taken into account when choosing the glue. Glues can be roughly divided into three groups according to durability:
- Weather-resistant glues. These glues have to be more durable than wood in all conditions. The joints have to endure different weather conditions, boiling and microorganisms. Phenol and resorcinol glues, and their mixtures fulfill these requirements.
- Moisture-resistant glues. These glues are suitable for indoor use, where the relative humidity may be quite high. This group includes melamine glues, some urea glues, and PVAc glues.
- Glues suitable for indoor use. These glues do not endure water soaking, but do endure a limited period in humid conditions. The most commonly used wood glues, urea and PVAc glues, belong to this group.
Selecting the right kind of glue