To provide a finished structure of a roof using a waterproof packing material with large tread break strength, facilitating the execution of the roofing materials and improving waterproofness by sticking a waterproof packing material with a cut-off part and bending the cut-off part.

Regarding to the waterproof packing material, double-sided tapes are installed on both obverse and reverse faces of a waterproof plate body and a slant cut-off part extending from the both sided tape at the obverse side to the substantially central part of the plate thickness of the waterproof packing plate body is formed as a feature.