Pyrrhotite Links from Charles Vidich

Listed below are links to two online articles that indicate pyrite in the soil can cause unstable foundations. The article states: "Anderson & Cobb (2008) have reported similar serious structural damage occurring in structures built on top of shale containing pyrite and sulfates, producing severely-cracked foundation walls and floor slabs."

According to the USGS, "Pyrrhotite is related to the more common and well-known mineral pyrite, also known as Fool’s Gold. Pyrrhotite differs from pyrite because it has less sulfur and is far more reactive to water than most pyrite." 

According to the American Geosciences institute "If pyrite or pyrrhotite are present in the rocks underneath buildings, the swelling can push on the foundation, walls, and basement floor of the building, causing cracks and other structural damage. In some cases, groundwater can then transport sulfates into the cracked foundation, causing further damage."

Here is the link to the website of the American Geosciences institute:

https://www.americangeosciences.org/critical-issues/faq/how-do-pyrite-and-pyrrhotite-damage-building-foundations#:~:text=If%20pyrite%20or%20pyrrhotite%20are,cracked%20foundation%2C%20causing%20further%20damage.

Here is the link to the InspectApedia website:

https://inspectapedia.com/structure/Foundation_Component_Damage.php