At a 1978 colloquy in which restorers, scientists and historians from all parts of Germany participated, it was decided to recommend the acrylic-total-impregnation process in cases when stones were beyond treatment with ethyl silicates or other consolidants. A plant erected in 1979 with this objective is described. It comprises a hall housing the nine main elements of which a combined vacuum and pressure tank are the main parts. All steps of the process are automatically recorded. The stone is impregnated after thorough cleaning and drying. Immersion takes place under partial vacuum at about 80°C. Impregnation is achieved when the monomer surrounding the stone is subjected to high pressure. The addition of special adhesive agents increase the chemical bonding. The stone gains in flexural strength (700%) and resistance to abrasion (500%). The appearance of the treated stone is of a wet surface unless special methods are used. After seven years of application, as under test conditions of accelerated aging, no cracking has been observed. Whole walls cannot be treated unless they are dismantled. Most difficulties encountered in the early stages of this process have been overcome. Some examples of the objects treated are given and illustrated. The price of the treatment is given (in DM per kilogram).