Pyrite Expertise

The pyrite is a common iron sulfide in the form of small grains in several types of rocks. It’s found almost everywhere, in rather small quantity (approximately 1%). One thus finds some, in the embankment under the concrete floors of the basements and residential garages. One of the shapes of the pyrite can oxide with humidity thus causing a swelling on the level of the embankment. This swelling can cause cracks or damage the structure of the masonry which is found on the embankment.

In the Quebec area, cases were indexed and now the phenomenon is more intensive. Contrary to the Montreal area, the phenomenon of the pyrite is unknown of the population. Thus several cases pass unperceived.

Symbiose Consultants Inc is able to carry out a test to detect the presence of the type of pyrite suspected to affect the structure of the buildings considerably. If this test proves to be positive, the customer could enjoy a governmental subsidy for the repair work due to the damage caused by the swelling of the pyrite in the embankment.

Symbiose Consultants Inc. accompanies the customer throughout the process of intervention, of detection and until the evaluation of the methods of decontamination are complete.

Symbiose Consultants Inc. supplements the required forms, makes the steps and the communications necessary to the result of the project. The swelling of the embankments of foundations can cause a cracking of the flagstone in the floor of the basement and in the garage. Sometimes, the damage also touches the walls of foundations but only the walls which surround the garage.


Sometimes, the embankment used with the basement is not same quality as the one used under the garage. Sometimes, it acts of the same embankment. One cannot predict, even when there is damage with the garage, if there will be or not damage with the basement. Swelling causes a rising of the flagstone. Cracks, often in the shape of cross or star, appear. The gypsum formation at the time of the chemical reaction can emphasize cracks and a white powder comes out of it. One notices, in certain cases, the unevenness of the floor and the setbacks of the cracks. It is rare that structural elements (columns or load-bearing walls) are pressed on the flagstone. If it is the case however, rising can cause structural damage with the building. Then it is very important to consult a professional.

À Rivière-des-Prairies, un beau cas avec un fort bombement du plancher et de la poudre de gypse en abondance.Céramique gonflée

The partitions pressed on a flagstone which is raised can present signs of bending or deform the floors. Cracks can appear on the gypsum facings. The doors can become more difficult to open or close, etc.

Haut de la pageSupervising the Evolution of the Phenomenon

The phenomenon of swelling slowly evolves, except in some rare cases. The specialists estimate that the movements range on average between 1 and 5 mm per year. At the end of a few years, the reaction stops.

It is important, before considering expensive work, to evaluate the extent of the disorder and their real impact on the quality of life in the building. Important rising which cause damage with the structure of the building will require urgent work. To the other extreme, an owner who notes some fine cracks in his garage could decide very well "to live with"!

If you are not convinced of the need for making an evaluations or work, we suggest you follow the evolution of the phenomenon closely. Make an inventory of the cracks. Measure them. Draw a sketch of cracking. Place bench marks which will enable you to see whether the cracks increase and widen. Then periodically return to remake your examination in order to see whether the phenomenon continues to evolve and at which rate. Take note, at the time of these examinations, of the date of the, the outside temperature and the ambient temperature.

Swelling being fed by moisture and oxygen, ensure yourself to limit to the maximum the infiltration of water and air. Avoid washing your car above the cracks!

Use a good drainage around the house.

The slope of the ground should bring surface water far from the foundations. The water of the gutters should be channeled far from the walls.

Limit the infiltration of air by clogging up the cracks.

In the garage, avoid heating too much in the winter.

Haut de la pageBe wary of the imitations!

The phenomenon of swelling of the embankments can be confused with other problems which present similar symptoms. The quality of construction being what it is, almost all the flagstones of residential buildings are not made out of reinforced concrete and present fine cracks laid out in random ways. These cracks can result from a "normal aging" and do not require work. Your building could also be affected by other problems of foundation, for example, a rising by the action of freezing, a subsidence under the soles, the swelling of clays, etc

In certain cases, a professional could determine the cause of the damage by a visual examination. In the majority of the cases however, only an analysis in a laboratory of a sample of the flagstone, embankment and subjacent ground will make it possible to determine with certainty if it is indeed a swelling associated with the pyrite. This analysis, whose conclusions are accompanied by an professional insurance responsibility, could in particular protect your rights to additional clause setting-up of a possible program from subsidy or, if you plan to sell your property.

Note that the less important the damage is, the less it is easy to distinguish the problem of pyrite of the other possible causes of the damage.

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