Wood glues are classified from D1 to D4 according to their moisture resistance, with each class suited to different levels of exposure. The classification follows the DIN EN 204 standard and indicates the environmental conditions for which each adhesive is designed.
D1 glues are intended for interior use with low humidity exposure, such as furniture and components in dry rooms.
D2 glues can withstand occasional exposure to higher humidity or short-term moisture and are commonly used in interior joinery.
D3 glues are suitable for areas with frequent short-term moisture exposure, such as kitchens or bathrooms, and are among the most widely used wood glues in furniture making.
D4 glues offer high water resistance and are suitable for heavily used interior applications as well as protected outdoor use.