Are OSB board waterproof?

Are OSB board waterproof? 14 Apr 2021

OSB can become irreversibly swollen, especially at the edges when excessively wet. You need to know that OSB absorbs even a little amount of water very slowly. Oriented strand board is resistant to water, but this doesn't mean that it is waterproof. Heat-cured resin adhesives (which coats and bonds the strands to form panels) are waterproof. However, its cutting and sanding can damage the protection and expose unprotected wood to moisture damage. The exposed grain acts like a sponge and draws in moisture which causes the strand to swell. Buy 15mm OSB Board UK