Pyrite inspection & testing

Pyrite inspection & testing

QualiTAM offers a comprehensive approach to pyrite testing. Our team of experts are proficient and accredited in sampling, testing and management of situations where pyrite damage is suspected. All our tests are carried out under the Protocol CTQ-M200. All samples are submitted to an accredited lab in order to analyze the swelling potential of backfill (known as the petrographic index swelling potential – PEPI).

When testing inspection and testing is complete, you will receive a detailed report outlining the level of pyrite present, recommendations for a remediation and expert insights on how to best avoid future defects.

What is Pyrite

Pyrite backfill and the damage it can cause to homes and commercial buildings is a worrisome and expensive defect to remedy in certain areas of Quebec. Gravel is always placed under concrete slabs in basements and garages and under certain conditions, the presence of pyrite mixed with the gravel can cause slabs to lift several millimeters.

Pyrite is a common mineral (Iron Sulphide), of which traces are often found in sedimentary type rock used to make crushed stone for backfill. In the presence of water and oxygen the pyrite crystals expand and swell, which can cause any retaining structures such as floors and walls to crack and swell over time.

Signs of pyrite damage

  • Star shaped cracks in concrete slabs
  • Heaving and bulging of the floor slab
  • Appearance of a fine white powder coming from the cracks
  • Cracks over and around doors and at wall junctions, when in contact with floor slab.

Zones at risk

It is recommended to proceed with soil tests in the following specific areas (other regions could be affected as well):

  • Laval – Laval-des-rapides, Duvernay, Ste-Dorothée.
  • Montreal-East – Rivière-des-Prairies, St-Léonard, Pointe-aux-Trembles, Repentigny, Le Gardeur.
  • Montreal-West – Dorval, Pointe-Claire, Dollard-des-Ormeaux, Pierrefonds, île Bizard.
  • South Shore – Boucherville, Brossard, La Prairie, Longueuil, Saint-Bruno, Saint-Hubert, Varennes.
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Also find us on the network of Outremont's home inspectors