Pyrite, also called Fool's Gold, is a distinctly golden coloured mineral that contains a mixture of iron and sulphur. Pyrite can be found all over the world.

Pyrite is sometimes found in the broken stone used as fill under a house foundation. If it gets wet, it can oxidize, causing the stone fill to swell.

Garage floors often crack due to the snow and water brought into the garage in the winter. Basement slabs can also heave and crack due to the swelling of the fill under the concrete slab. If the swelling occurs under the slab or under the garage floor, the problem might simply be cosmetic in nature. If, however, the swelling occurs in the fill under the foundation footings, there can be structural problems - the foundation walls can lift and crack, and the whole building can be thrown out of level.

The only thing that can be done to solve the problem of swelled pyrite is to remove the fill. Unfortunately, this usually involves jackhammering the concrete and dismantling significant portions of the foundation. The whole process can be very expensive.

The Government of Quebec has a pyrite grant program to help defray the costs of making these repairs. The Federal government and various municipal governments all support this program. If your building is located in a municipality that participates in the program, and your pyrite problem does NOT only affect your garage, you could be entitled to financial support of up to $18,000 for a single-family home, and up to $45,000 for a multi-unit building.