To repair a rain leakage or water leakage in storage structures resulting from crazes and cracks which are present in or generated in concrete building structures through a process using facile tools such as atomizers, sponge rolls, etc. at a low cost, and also to repair a leakage even when the point causing the rain leakage or water leakage cannot be specified by allowing the repairing material itself to flow into the crazes and cracks and form a waterstop mass.

A spread-type rain-leakage inhibiting material comprises a suspension A containing from 0.1 to 30 wt.% water-insoluble inorganic powder and a liquid B containing 0.1 wt.% or more acrylic copolymerized emulsion which contains 1% or more polyacrylic acid and has a degree of polymerization of 1,000 or larger. Leakage is repaired using the spread-type rain-leakage inhibiting agent for concrete structures comprising treatment agents A and B, by first spreading the treatment agent A and then the treatment agent B, or inversely, on the crack part of the concrete causing the rain leakage.