Is OSB water-resistant?

OSB has limited water resistance, which mainly depends on its grade. OSB 1 and 2 are not suitable for humid environments, while OSB 3 and 4 offer better moisture resistance.

OSB 3, the most commonly used for interior fittings, can withstand temporary exposure to moisture but is not waterproof. This type of OSB 3 panel is perfectly suitable for:

  • Partitions in dry rooms
  • Subflooring under coverings
  • Interior furniture

For optimal protection, applying a water-repellent treatment or waterproof paint significantly improves its resistance. In damp areas like bathrooms, it's better to use panels specifically designed for such environments.

OSB remains an excellent choice for dry interior use thanks to its good value for money.