I have a maintenance account with a large building and have noticed that the granite on the outside of their building is crumbling and falling apart. This condition is getting worst every year especially during the spring months. What’s causing

This is a problem in northern climates where de-icing salts are used. During the winter months deicing salts are used to melt the snow and ice. When the weather warms, the salts are dissolved and carried into the granite. When the granite dries, the salts recrystallize and cause pressure within the granite causing the stone to crumble. Unfortunately there is not much that can be done to fix this problem other than to eliminate the deicing salts.