Garage attic drywall over OSB

A homeowner in Grand Rapids, Michigan posted a question on a building-science forum about an unfinished attic space above an insulated but unheated garage. The attic has exposed OSB sheathing (the plywood-like board under a roof), ridge vents, and soffit vents, and the rafters are walkable. The homeowner is considering adding drywall directly over the OSB and has gotten conflicting opinions on whether that's a good idea, particularly whether it could trap moisture and lead to mold since there's no heated living space nearby.

At the time this was posted, no one had answered yet, so there's no expert guidance to pass along. This is really a reminder of a common question for anyone with an attached garage that has an attic or roof space above it: adding finishes like drywall to an unconditioned, vented attic changes how air and moisture move through that space, and getting it wrong can create condensation problems on the underside of the roof sheathing.

If you have a similar unheated garage attic with ridge and soffit vents, it's worth understanding how your own setup handles moisture before adding drywall or any other interior finish up there. Venting, insulation placement, and whether the space stays unconditioned all affect whether trapped moisture becomes an issue. A local energy auditor or building-science-savvy contractor can look at your specific vents, insulation, and climate to confirm whether drywalling over bare sheathing in a space like this is safe for your house.