A method for sealing and/or filling of cracks, voids, flaws and cavities in a building structure, the method comprising steps of i) Providing a multiple-component composition, ii) Mixing the constituents contained in the multiple-component composition with water such that in the thus resulting mixture, the weight ratio of the total amount of said at least one water-soluble (meth)acrylic compound to the amount of water is in the range of 0.1:1 to 5:1, iii) Applying the mixture to the site to be sealed/filled in the building structure and letting the mixture to form (meth)acrylic hydrogel, wherein the multiple-component composition comprises constituents: a) at least one water-soluble (meth)acrylic compound, b) at least one free radical initiator, c) at least one benzoate, d) optionally at least one catalyst for free radical formation, wherein the content of said at least one water-soluble (meth)acrylic compound is 60.0 - 99.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present and wherein the at least one water-soluble (meth)acrylic compound has a solubility of at least 5 g/100 g water at a temperature of 20°C and wherein the content of said at least one benzoate is 0.05 - 15.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present. i) Providing a multiple-component composition, ii) Mixing the constituents contained in the multiple-component composition with water such that in the thus resulting mixture, the weight ratio of the total amount of said at least one water-soluble (meth)acrylic compound to the amount of water is in the range of 0.1:1 to 5:1, iii) Applying the mixture to the site to be sealed/filled in the building structure and letting the mixture to form (meth)acrylic hydrogel, wherein the multiple-component composition comprises constituents: a) at least one water-soluble (meth)acrylic compound, b) at least one free radical initiator, c) at least one benzoate, d) optionally at least one catalyst for free radical formation, wherein the content of said at least one water-soluble (meth)acrylic compound is 60.0 - 99.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present and wherein the at least one water-soluble (meth)acrylic compound has a solubility of at least 5 g/100 g water at a temperature of 20°C and wherein the content of said at least one benzoate is 0.05 - 15.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present. a) at least one water-soluble (meth)acrylic compound, b) at least one free radical initiator, c) at least one benzoate, d) optionally at least one catalyst for free radical formation, wherein the content of said at least one water-soluble (meth)acrylic compound is 60.0 - 99.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present and wherein the at least one water-soluble (meth)acrylic compound has a solubility of at least 5 g/100 g water at a temperature of 20°C and wherein the content of said at least one benzoate is 0.05 - 15.0% by weight, based on the total weight of the multiple-component composition excluding the amount of water that may be present.