We consider a model of polymeric modifying agent that may increase the water resistance performance of wood and other properties of modified wood. To analyze the structure and functional characteristics of an oligomer proposed, we employ the theory of adhesion, the theory of cohesion, and the theory of diffusion. We design the dimensions and molecular-mass characteristics of molecules of the modifying agent on the bases of relationships describing the adsorption of macro-molecules against porous materials with taking account for capillary-porous structure of wood. Using monomeric compounds that are in vat residue of production of synthetic rubber, we perform the synthesis of the polymeric modifying agent. We propose a statistical model that accurately describes the properties of modifying wood for investigated range of technological parameters.