A composite wood panel having a first and a second longitudinal edge comprising an essentially parallel first surface and second surface, a core, a spacer integrally formed in or attached in the core on at least the longitudinal edges wherein the spacer extends from an edge a pre-determined distance whereby upon placing one panel adjacent to a second panel a spacer of the first panel will abut a spacer of or an edge of a second panel thereby forming at least a first aperture between the adjacent panels wherein an aperture is located between adjacent edges of the panels. A spacer can push into its panel upon linear expansion of a panel. The spacer can be, e.g., a tongue, edge profile, or separate spacing material. Methods for making and using panels are disclosed.