Disclosed is a curable composition with enhanced curing time at ambient temperatures, the curable composition including (a) a resin, e.g., 4,4′-isopropylidenediphenol-epichlorohydrin copolymer and (b) one or more curing agents, wherein a ratio of a weight percentage of the resin to a weight percentage of the curing agent or curing agents is from about 12:1 to about 15:1. Also disclosed is a method of curing a cured-in-place liner, wherein the cured-in-place liner contains the above curable composition.