The present report deals with the properties of solutions of the epoxy resins when they ace used to reinforcement of the damaged historical objects. Besides the advantageous qualities such as low viscosity and chemical and biological resistance, they have also negative features, especially orispness, which has essential meaning in case of reinforcement of a very damaged wooden surface. Before they are used epoxy resins must undergo the process of making elastic. It consists of the so-called internal and external plasticization. In the first case we add to the resin chemical compounds capable of reacting with it, like: polysulphides, polyesters, acid anhydrides. In the latter case, however, we add substances not reacting with it, e.g. dibutyl phthalate, which is one of the constituents of the composition called in Poland Epidian 5. Epidian 5, modified by dibutyl phthalate, underwent narrow tests in view of being used in restoration works consisting of the reinforcement of wood. It has been found, as the result of the research, that dibutyl phthalate does not cause any visible destructive changes in hardened resin films but gives it elasticity and, what is more, does not make the wood swell. Optimum proportion is 20 per cent of dibutyl phthalate and 80 per cent of resin. With Epidian 5 a great number of historical wooden carvings has been preserved.