The many uses of plywood
A huge variety of plywood panels are available, for a wide range of uses.Each type of plywood displays specific characteristics. Moreover, the main criterion when choosing a plywood is whether it will be used indoors or outdoors.
Two main criteria determine where plywood can be used: its basic characteristics and the species of timber from which it is made.
Plywood is notably defined by its bonding class (determined according to standard NF EN 314-2). This bonding class determines the conditions in which the plywood can be used:
- Class 1: dry interior environments
- Class 2: humid interior environments
- Class 3: exterior applications
All plywood can be used indoors: the user will base their choice on the appearance and colour of the timber species. For exterior use, it is important to opt for bonding class 3 and naturally durable species, or species made durable by certain treatments.
In all cases, the durability of plywood panels exposed to the elements invariably depends on how closely installation guidelines have been followed and on the application of a suitable finish. In this context, the NF Contreplaqué EXTERIEUR CTB-X quality label is a very useful point of reference: it vouches for the plywood’s suitability for exterior applications.
In France, three main species are used in the manufacture of raw plywood: okoume, poplar and maritime pine.
Physical and mechanical characteristics of plywood
Characteristics can vary depending on the variety (or varieties) of wood used, panel thickness and the number of plies comprising the plywood. It should be highlighted that these characteristics are extremely homogeneous and reliable, due to the elimination of defects during manufacture.
Some applications place great emphasis on aesthetic appeal, requiring plywood that is free of blemishes and knots, while other applications do not require such a uniform appearance, even if the level of performance specified is the same. Plywood is also classed according to surface appearance (based on standards NF EN 635-2 and NF EN 635-3). Two classifications (hardwood, including tropical varieties, and softwood) allow plywood to be graded from 1 (optimal visual appearance) to 4 (significant marks).