Abstract: The present invention relates to thermoset epoxy resin waterproofing membranes for structures such as roofs comprising: (a) one or more epoxy resin(s) having an average of at least 1.5 epoxy groups per molecule; (b) a liquid amine terminated polyamide prepared by reacting at least one C18-50 dicarboxylic acid and an aminoalkylpiperazine in a ratio of moles of aminoalkylpiperazine to equivalents of carboxyl group in the acid of greater than 0.75:1; (c) one or more optional polyamine(s); (d) one or more optional filler(s); and (e) one or more optional modifying resin(s) wherein the tensile modulus of the thermoset epoxy waterproofing membranes is less than 200,000 psi and the tensile elongation of the thermoset epoxy waterproofing membranes is greater than 20%.