High-risk areas for pyrite: Broker responsibilities 

Pyrite is an iron sulphide molecule present in the stone fill used in construction. It may therefore be found around foundation drains and under the concrete slabs of the cellar or the garage. Under certain conditions, pyrite can oxidize and produce a sort of white powder that swells, causing, among other things, the slab to lift and producing cracks in the foundation and partitions. These problems may appear several years after construction.

Pyrite issues have been identified in 91 cities of the Greater Montreal area. However, the highest-risk areas are the South Shore (from Châteauguay to Varennes and from the St. Lawrence River to the Richelieu River), the East End of Montréal (including Rivière-des-Prairies, Pointe-aux -Trembles, Repentigny) and the Montreal West Island (including Lachine, Dorval, Dollard-des-Ormeaux, Pointe-Claire, Kirkland, Pierrefonds-Roxboro and Beaconsfield).

The Organisme d’autoréglementation du courtage immobilier du Québec (OACIQ) urges its licence holders to inform their clients selling and buying properties located in these risk zones of the problems related to pyrite and to recommend the specific actions described below. These recommendations are intended to protect sellers and buyers, as well as the real estate intermediaries who have the ethical obligation to advise them properly. The utmost transparency will favour the success of real estate transactions made in this context.

Recommendations to make at the Brokerage contract - Sale stage (regardless of whether the contract is signed or not)

Your broker must inform you of the pyrite problem in the risk zones and the consequences this may have for the sale of your property. He must tell you:

  • that he has the duty to inform every buyer about the pyrite, even if the property does not seem to be affected;
  • that you must complete the mandatory form Declarations by the seller of the immovable (or its version for divided co-ownership), when required in residential matters, indicating whether or not you are aware of the presence of pyrite;
  • that an expertise should be done quickly to determine if pyrite causes or may cause problems;
  • that a buyer does not usually bear the cost of an expertise and that he cannot have it done without the owner's authorization;
  • that if a problem is detected, it must be corrected or the selling price must take into account this problem, otherwise, the property may be difficult to sell;
  • that a copy of the expert report (and, if applicable, a copy of the detailed invoice for the repairs done) must be transmitted to any buyer, regardless of the result of the analysis.

Recommendations to make at the Promise to purchase stage

If you are the buyer, your broker must obtain all the necessary information from the seller’s broker, who is obliged to supply it. 

Whether he is the seller’s broker or the buyer’s broker, the broker involved in the transaction must:

  • inform the buyer of the problems caused by pyrite in the risk zones, even if the property does not seem to be affected;
  • inform the buyer of the seller’s declarations regarding the presence of pyrite;
  • inform the buyer of the fact that only an expertise can determine whether a property may or may not be affected by pyrite;
  • if the expertise has been done, transmit a copy of the results of this analysis to the buyer and the building inspector;
  • inform the buyer that, before even presenting a promise to purchase, he may consult his own expert to interpret the results of this expertise;
  • if repairs have been done, transmit a copy of the invoices explaining the nature of the work performed to the buyer and the building inspector;
  • If the expertise has not been done, recommend to the buying client that he make a promise to purchase conditional upon this analysis (generally at the seller’s expense) and on its results (allow for about three weeks). This condition can be indicated using the recommended form Annex – Expert report. Note that it is up to the buyer and not the broker to decide whether or not he is satisfied with the results of the soil expertise.

A real estate broker must not specify, in a Promise to purchase, a clause providing for a pyrite test with a percentage representing the threshold beyond which the buyer may withdraw his Promise to purchase. The real estate broker is not authorized to set such a threshold, which is insufficient to assess the risks associated with the presence of pyrite.

Note that in all cases real estate brokers and agencies may not conceal information concerning an immovable on the pretext that it may hinder his sale or that the Promise to purchasehas already been accepted.

Transactions already in progress

If he learns that an immovable for which a Promise to purchasehas already been accepted is located in a risk zone, but the deed of sale has not yet been concluded, the broker must:

  • inform the seller and the buyer that the immovable is located in a risk zone, meaning places where several cases of swelling of the stone landfill have been noted;
  • inform the seller that it is the real estate broker's duty to disclose this information to any potential buyer;
  • recommend to the buyer that he ask the seller for authorization to have an expertise of the stone landfill done, normally at the seller's expense;
  • recommend to the seller that he agree to have the expertise done even if the results may compromise the agreement already concluded, which is preferable to the legal complications that can be feared in the event of a refusal.

Analysis of backfills should be carried out by a recognized laboratory

When an analysis is required in a real estate transaction, the OACIQ reminds its licence holders of the importance of dealing with recognized laboratories that apply the methodology laying down the measures to be observed when visually inspecting disorders affecting a property and when sampling and analyzing backfills (methodology CTQ M-200). Although voluntary, this methodology is currently the only one recognized by the competent authorities.


  • No one can conceal information on the pretext that it may hinder the sale of a property.
  • If the property covered by a real estate transaction is not located in a risk zone, the broker must nevertheless conduct a visual examination of the premises, particularly the slab and the foundation, and inform his client and the building inspector of his observations.
  • A broker must not give an opinion on the origin of cracks. He is neither a building inspector nor a soil analysis specialist.
  • A building inspection alone is not enough to detect with certainty problems that result from pyrite.
  • The broker must ask the seller whether repairs have been done. If this is the case, he must try to obtain a copy of the invoices describing the nature of the work performed.
  • A real estate broker or agency must never advise clients to deal with an unrecognized laboratory.

Several organizations have collected a lot of information about pyrite:

Association des consommateurs pour la qualité de la construction

Association provinciale des constructeurs d'habitations du Québec

Régie du bâtiment du Québec


Last updated on: August 26, 2019
Article number: 207037