04/06/2013 05:10 EDT | Updated 06/06/2013 05:12 EDT

Homeowners demand $25M from Ottawa for structural damage

Several groups in Trois-Rivières are demanding millions of dollars from the Canadian government for damage caused by pyrrhotite, a mineral that can lead to cracks in concrete structures.

About 500 homeowners whose houses were built with concrete that contained pyrrhotite attended a meeting organized by the Coalition Proprio-Béton, a group that is campaigning to have the homeowners compensated.

NDP Members of Parliament, Robert Aubin and Ruth Ellen Brosseau, also attended the information session. They are demanding that the federal government hand over $15 million to help the homeowners.

The Coalition Proprio-Béton, on the other hand, said the Canadian government should pay $25 million to help cover the cost of repairs.

The province of Quebec already has a $15 million fund to help cover damage to homes and properties caused by the mineral.

The coalition wants to tap into unused funds from a compensation program for pyrite in Montreal and reclaim the goods and services tax (GST) paid to repair homes affected by pyrrhotite.

The coalition and a consumers' association for quality in construction met with Quebec's Labour Minister Agnès Maltais in Shawinigan.

She said she would take a look at the current warranty guidelines on new homes.

The presence of pyrrhotite in concrete can cause cracks in the material. These cracks can affect the building's structure and even cause it to crumble.


Pyrrhotite and pyrite: the differences

"Pyrrhotite is a mineral species composed of iron sulfide and is of a bronze yellow color, blackening when exposed to air. When it crystallizes in blades, pyrrhotite can produce cracks in the concrete structures."

"Pyriteis a mineral which is found in stone and produces sulfuric acid when it oxidizes upon contact with humidity and oxygen. When this phenomenon occurs under foundations, it can cause the heaving and cracking of the concrete slab."

(Source: Quebec's building authority)