Patent ID: 8225546

Claim:
A plant cultivation structure for rooftops of buildings, comprising: a first layer comprising a waterproof layer arranged directly on top of a rooftop surface; a second layer comprising a root-preventing layer formed directly on top of the waterproof layer to prevent extrusion of plant roots into the waterproof layer; a third layer comprising a water retention, supply, and drainage structure arranged directly on top of the root-preventing layer, comprising a plurality of integrated water retention parts and water drainage parts; and a fourth layer comprising a soil layer for cultivating plants, said soil layer being provided in an upper portion of the water retention, supply, and drainage structure; wherein the root-preventing layer consists of: a resin film adapted to prevent the extrusion of the plant roots, said resin film having a thickness of between approximately 75 microns and 300 microns, a film surface of the resin film abutting the water retention, supply and drainage structure and being formed by a painted-on layer that comprises an acrylic urethane paint adapted to improve adhesiveness, weatherability, and strength of the resin film; an adhesive layer formed on a back face of the resin film abutting the waterproof layer and having a thickness of approximately 30 microns; a cover tape, which has an adhesive layer on a back face thereof and is adapted to prevent the extrusion of the plant roots, is affixed to mutually abutting or overlapping parts of the resin film to prevent the extrusion of the plant roots, and a thickness of the adhesive layer of the cover tape is formed to be smaller than a diameter of extruding tips of the plant roots, said thickness being approximately 30 microns.