What does MR or WBR mean?

MR | Bonding suitable for indoor use - old designation

MR stands for ‘Moist Resistant'. Oddly enough, this name sort of puts you on the wrong track. A sheet with MR bonding is in fact an interior bonding and can therefore only be used in dry rooms, so it should not be considered moisture resistant.

WBP | Bonding suitable for outdoor use - old designation

WBP stands for 'Water Boil Proof' and indicates that the bonding is suitable for exterior applications. Always pay close attention to the type of wood, as some types of wood are not water resistant, despite the use of waterproof glue. Whereas in the case of MDF the wood fibres are so small that the bonding determines how water resistant the sheet is, in the case of plywood, thin sheets of wood are used which are glued together crosswise. As a result, the type of wood also determines the water resistance of a panel. An example is birch plywood. This material is glued waterproof by default, but not suitable for outdoor use without protection. Marine plywood, on the other hand, is a tropical hardwood species that is also glued waterproof, but suitable for outdoor use. This type of wood is much stronger and more resistant to weather influences.

Nowadays, the bonding of plywood is indicated as follows:

EN 314-2 | Class designation (humid) rooms

This standard is also an indication for the bonding of wooden sheets and distinguishes between 3 classes:

EN 314-2 | Class 1: suitable for interior applications in dry rooms

EN 314-2 | Class 2: suitable for interior applications in moist rooms and/or covered/protected outdoors

EN 314-2 | Class 3: suitable for (unprotected) outdoor applications