A process for the production of a rigid polyurethane foam or rigid polyisocyanurate foam, comprising the reaction of a) at least one polyisocyanate and b) a polyol composition, where the polyol composition comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound selected from the group consisting of dicarboxylic diesters of the general formula: where R1 and R2 are mutually independently H or an alkyl moiety having from 1 to 6 C atoms; and R3 and R4 are mutually independently an alkyl moiety having from 1 to 18 C atoms, and where at least one blowing agent is used during the reaction, where blowing agent used comprises water or water in a mixture with another physical or chemical blowing agent, where the other blowing agent is selected from the group consisting of propane, n-butane, iso- and cyclobutane, n-, iso- and cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, 1,3,3,3-tetrafluoropropene, 1,1,1,2,3-pentafluoropropene, 1,1,1,4,4,4-hexafluorobutene and 1-chloro-3,3,3-trifluoropropene, and insofar as water is used as sole blowing agent, the quantity of water used is in the range from 1 to 10% by weight, based on the weight of the polyol composition, or insofar as water is used in combination with another blowing agent, the quantity of water used is in the range from 0.1 to 5.0% by weight, based on the weight of the polyol composition. a) at least one polyisocyanate and b) a polyol composition, where the polyol composition comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound selected from the group consisting of dicarboxylic diesters of the general formula: where R1 and R2 are mutually independently H or an alkyl moiety having from 1 to 6 C atoms; and R3 and R4 are mutually independently an alkyl moiety having from 1 to 18 C atoms, and where at least one blowing agent is used during the reaction, where blowing agent used comprises water or water in a mixture with another physical or chemical blowing agent, where the other blowing agent is selected from the group consisting of propane, n-butane, iso- and cyclobutane, n-, iso- and cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, 1,3,3,3-tetrafluoropropene, 1,1,1,2,3-pentafluoropropene, 1,1,1,4,4,4-hexafluorobutene and 1-chloro-3,3,3-trifluoropropene, and insofar as water is used as sole blowing agent, the quantity of water used is in the range from 1 to 10% by weight, based on the weight of the polyol composition, or insofar as water is used in combination with another blowing agent, the quantity of water used is in the range from 0.1 to 5.0% by weight, based on the weight of the polyol composition. where the polyol composition comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound selected from the group consisting of dicarboxylic diesters of the general formula: where R1 and R2 are mutually independently H or an alkyl moiety having from 1 to 6 C atoms; and R3 and R4 are mutually independently an alkyl moiety having from 1 to 18 C atoms, and where at least one blowing agent is used during the reaction, where blowing agent used comprises water or water in a mixture with another physical or chemical blowing agent, where the other blowing agent is selected from the group consisting of propane, n-butane, iso- and cyclobutane, n-, iso- and cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, 1,3,3,3-tetrafluoropropene, 1,1,1,2,3-pentafluoropropene, 1,1,1,4,4,4-hexafluorobutene and 1-chloro-3,3,3-trifluoropropene, and insofar as water is used as sole blowing agent, the quantity of water used is in the range from 1 to 10% by weight, based on the weight of the polyol composition, or insofar as water is used in combination with another blowing agent, the quantity of water used is in the range from 0.1 to 5.0% by weight, based on the weight of the polyol composition.