Abstract: A longitudinally extending construction panel is adapted to interconnect with a like panel to form a waterproof connection. A leverage arrangement including a fulcrum adjacent mating surfaces of the panels is utilized to seat the mating surfaces. Rotation of a panel about the fulcrum permits the mating surfaces to be pressed together with a force sufficient to deform the contact surfaces together to provide a watertight seal therebetween. The width of the rotated panel provides a lever arm to aid in application sufficient force to accomplish the sealing effect. The fulcrum in cooperation with a support leg and a base plate, forms a water tight drain channel below the sealed contacting surfaces. Control of the dimensions of the panel permits lateral movement between assembled panels.