Manufacturers and the APA recommend leaving a 1/8-inch gap between wood structural panels. The reason for this is because wood expands when exposed to moisture or gets wet. If the panels are installed tight against each other, your panels will expand and the result is buckling, uneven roofs, walls and floors.
In its video; ‘Prevent Buckling with Proper Spacing’, the APA shows how to avoid buckling with correct panel spacing.
Watch the video here: