“In the study, laboratory dishes partially filled with water were set upright and sealed at the mouth with samples of both sheathing materials,” EIMA said in an October press release. “The water evaporated from the dishes capped with plywood, but did not from the OSB-covered dishes. In fact, the OSB-covered dishes still held water eight months later.”
A later release from EIMA suggested, “When used in a wall assembly, designers should be aware of OSB’s characteristics and how it interacts with moisture.”