A method for repairing and/or waterproofing and/or insulating and/or reinforcing and/or restoring the structural integrity of wall systems, which it consists in providing spaced injection holes within a wall system in a manner suitable to pass through cavities that exist in the wall system, inserting injection tubes in these holes, and then inserting a substance that expands after injection as a consequence of a chemical reaction so that the substance reaches the cavities connected to the injection holes or are proximate thereto, the injection tubes being, preferably gradually retracted along the injection holes in the opposite direction with respect to insertion, to allow the substance diffusing in cavities crossed by the injection holes or proximate thereto.