A panel for connection with other panels, comprising a rectilinear base member having outer edges, a first rectilinear side member extending from one edge of the base member, the first side member having a first lip extending from an outward edge of the first side member and away from the base member, the first side member further having a second lip extending from an outward edge of the first lip and toward the base member and at an angle between about zero and 90 degrees with respect to the first lip, and a second rectilinear side member extending in substantially the same direction as the first side member, from an opposite edge of the base member, the second side member having a third lip extending toward the base member. Related structural members, enclosures, posts, spray booths and methods for assembling the same which include similar features are provided.