Some older buildings are struggling with pyrite or pyrrhotite issues beneath their foundations. How to recognize the signs? What are the actual consequences? Are there any financial assistance programs? Here is everything you need to know to make an informed decision.
What is pyrite?
Pyrite, or iron sulfide, is a golden mineral nicknamed “fool’s gold”. It was formerly used as backfill to level the ground before a house’s foundations were built. Unfortunately, when in contact with moisture, pyrite produces sulfuric acid, which can lead to foundation cracks or even the heaving of concrete slabs.
Quite often, this type of material is detected in properties built during the 1980s.
What is pyrrhotite?
Bronze-yellow in color and darkening when exposed to air, pyrrhotite is a mineral composed of iron sulfide When it oxidizes upon contact with moisture and oxygen, it damages the concrete by creating cracks.
Homes built between 1996 and 2008 are those most primarily affected by this problem.
How to detect their presence?
The following signs may indicate the presence of pyrite:
- Sulfation
- Foundation cracks
- White powder around the cracks
- High humidity in the basement
- Uneven floors
For pyrrhotite, horizontal or star-shaped cracks are often observed in the concrete foundations.
What are the consequences?
Over time, the presence of pyrite or pyrrhotite leads to a deterioration of the foundations:
- Cracks
- Concrete heaving
- Water infiltration
- Structural damage
Obviously, these problems can influence a property’s market value and deter potential buyers. Furthermore, financial institutions may be hesitant to grant a loan, and insurance companies may refuse to cover damages related to these minerals.
Which regions are at risk?
Pyrite:
- Montérégie
- Châteauguay to Varennes
- The East End of Montreal Island: Rivière-des-Prairies, Pointe-aux-Trembles, Repentigny
- The West Island of Montreal: Dorval, Dollard-des-Ormeaux, Pointe-Claire, Kirkland, Pierrefonds-Roxboro, Beaconsfield.
Pyrrhotite:
- Mauricie (Trois-Rivières)
- Centre-du-Québec
How to get rid of it?
Unfortunately, there is no way to neutralize the oxidation process of pyrite or pyrrhotite. The only remaining option is therefore to have your foundation inspected and to remove all of the harmful minerals. This solution is permanent, but it comes at a cost. Before starting any work, it is advisable to have the damage evaluated by a contractor; they will guide you in establishing a budget and organizing the various steps.
Assistance programs
If you ever have pyrite problems, check if you are covered by the Guarantee Plan for New Residential Buildings. In addition, the RénoRégion and RénoClimat programs offer financial assistance to owner-occupiers for carrying out work on their property.
The Government of Quebec has established the Pyrrhotite Program, which provides financial assistance to homeowners whose foundations are damaged by the presence of pyrrhotite to carry out the necessary work.
Find out more right here: Programme Pyrrhotite — Volet I : aide financière pour la réalisation de travaux
Team up with a broker to ensure your protection.
Our brokers have a duty to inform you about pyrite problems in high-risk zones and their potential consequences. If they suspect the presence of these elements, they will recommend that you have an analysis performed. If the test is positive, the selling price must be adjusted accordingly or the seller must carry out the repairs.
Note that the building inspector does not take samples or perform any laboratory analysis during the inspection. These tests must be carried out by specialists. Hence the importance of working with a real estate broker; they will know which signs to look for and will help you make an informed choice.