POTENTIAL CAUSES OF THE PROBLEMa) Waterproofing Failureb) Lack of waterproofingSOLUTIONCarefully examine concrete walls of the basement. In case of an existing leakage, we should use WRM 500, a non shrinking, fast-setting, one-component repairing mortar. For the preparation of WRM 500 only water is needed. In a clean pot add 210 – 230 ml of water and gradually add 1 kg of WRM 500, stirring continuously with fast and strong moves, with a spatula, in order to create a homogeneous maze.Having worn protective gloves, shape the mixture and put it on the hole.Press gently for 3 minutes, until the mixture stabilizes completely.