Abstract: An improved waterproofing system for the concrete slab of a flat roof on a building is disclosed. The waterproofing system uses hollow plastic panels of designed size, different thickness, and groove and tongue joints for interconnecting the panels. A supplementary waterproofing layer may be installed using sheet membrane materials such as asphalt sheet, metal sheet and other sheets on vertical surfaces, especially the parapet of the roof. The invention further concerns a construction method for applying a fiber mesh reinforcement on the connection joint and for applying fluid-applied materials on the substrate with sheet membrane layers on vertical surfaces. The waterproofing layer of sloped step type, hollow plastic panels of different thickness, permits fast drainage of stagnant water, which inhibits weather damage to the waterproofing layer.

Abstract: An improved waterproofing system for concrete slab of a flat roof on a building is disclosed. The invention concerns a construction method for installing on the concrete substrate a waterproofing layer comprising hollow plastic panels of designed size, different thickness, and the groove and the tongue joint, and installing a supplementary waterproofing layer using sheet membrane materials such as asphalt sheet, metal sheet and other sheets on the vertical surface, especially the parapet of roof. The invention further concerns a construction method for applying fluid-applied materials after reinforcement with fiber mesh on their joint line to connect plastic panels on substrate with sheet membrane layer on the vertical surface. The waterproofing layer of sloped step type, hollow plastic panels of different thickness permits fast drainage of stagnant water, which inhibits weather damage to the waterproofing layer.