Is OSB board waterproof?

Is OSB board waterproof?

No, OSB (Oriented Strand Board) board is not waterproof. While OSB is made by compressing and gluing together small strands of wood with resin, it is still made of wood and is susceptible to water damage.

When exposed to water or moisture, OSB can swell, warp, and delaminate, which can compromise its structural integrity. Therefore, it is not recommended to use OSB in areas that are likely to be exposed to water or high levels of moisture, such as in bathrooms or outdoor applications.

To make OSB more resistant to moisture, it can be coated with a water-resistant layer or a sealant. However, even with these measures, it is still not considered fully waterproof. For applications that require waterproofing, alternative materials such as marine-grade plywood or cement boards may be more suitable.