Finlandia Hall in Helsinki, with Carrara marble panels, image from Wikipedia
Building stone has failed across climates from northern Europe to Cuba to Libya to Canada in marble quarried in areas equally as diverse, such as Vermont, Greece, Greenland, and Norway. Carrara marble, however, leads the field, in part because it is the most widely used marble in the world.
In their report, the authors made several observations:
- The higher the temperature variations, the higher degree of bowing.
- Higher humidity can lead to problems when water penetrates pore spaces.
- There is no correlation between panel size and thickness and tendency to bow.
- Bowing tends to be more pronounced on the southeast and southwest facades.
- More pronounced bowing occurs on the upper parts of buildings.
- No link has been found between anchoring system and bowing.
- Marble color doesn’t impact bowing.
- Pollution doesn’t impact bowing.
- At least a half-dozen previous authors have noted that bowing depends on the grain boundaries of the marble, which ultimately depends on the geologic history of the stone.
The authors recommend the development of a series of guidelines to choose, test, and produce marble panels. They conclude that “technically acceptable properties should…have very high priority when choosing a marble type for a building project, whereas today aesthetical properties are often considered as being of greatest importance even though the aesthetic problems will change rapidly for a nonsuitable marble as it deteriorates.” In other words, no matter how pretty and elegant the Carrra marble looked on Big Stan, when they failed, it was a monumental screw up that could have been avoided if the builders had been more concerned with function over style. Once again, it pays to pay attention to geology.