Corrosion of mineral building matenals is too little considered. Because minerals are porous, they corrode not only on the surface, but also internally. Chemical and physical damage both take place. Concrete exposed to sulfate solutions produces calcium aluminum sulfate hydrate which is water soluble. Most of the damage is the result of mistakes in the design and construction of the building materials. Concrete without calcium carbonate is described and the resistances of various building materials to outside influences are described. -- AATA