According to EN 300, there are four types of OSB, known as technical classes:
- OSB → general purpose non load-bearing boards for use in dry conditions (service class 1)
- OSB 2 → load-bearing boards for use in dry conditions (service class 1)
- OSB 3 → load-bearing boards for use in humid conditions (service classes 1 & 2)
- OSB 4 → heavy-duty load-bearing boards for use in humid conditions (service classes 1 & 2)
Among these, OSB 3 is currently the most used product in Europe.
Standard OSB boards have un-sanded faces and sharp edges, but boards with smooth/sanded faces and milled edges (2 or 4-sided „tongue and groove“ - T&G profiles) are also possible to manufacture.