Integrated water-soluble film is dissolved in the rubber asphalt waterproof sheet to secure adhesive strength on freshly cast concrete on the adhesion side of waterproofing layer on the floor slab. In addition, in order to determine whether the water in the concrete slurry can dissolve the water-soluble film sufficiently, the adhesive strength of the waterproofing sheet was compared between difference wetness condition at the upper part of the concrete specimen before the concrete casting.