The gas production is made in the digesters in the biogas facilities. Gas is formed after passing through certain processes, from the liquid fertiliser and organic wastes, pumped inside the digesters. It is required to made gas proof roof on it for the gas formed not escaping from the digesters having circular cross-sections. However this roof should be made up of elastic material. The flexible roof expands and the digesters volume increase for not increasing the pressure in the gas formation inside the digester. It is required that the pressure inside the digesters stays in minibar levels. Otherwise, gas explosions occur. Because of this digesters roofs are covered with EPDM membranes which are very flexible. The locking points inside the concrete are provided by PVC profiles produced specially.