Does the rock aggregate under the concrete slab of your building contain pyrite?

Sedexlab provides sampling and laboratory analysis services to assess the swelling potential (IPPG) of the rock aggregates under the concrete slab.

  • Over 35,000 pyrite tests since 1999
  • Carried out from A to Z by Sedexlab. No middleman.
  • Compliant with CTQ-M200 protocol requirements
  • Pyrite Swelling Potential Index (IPPG) put into context and explained in layperson’s terms.
Residential Building
$450.00 1 sampling (ex: basement)
$600.00 2 samplings (ex: basement and garage)
$150.00 Per additional sampling

TURNAROUND TIMES

Appointment : 1-2 days notice

Results : 1 day

Schedule Sampling

What You Obtain

A written report signed by a Certified Professional Geologist describing:

  • Identification and visual inspection of the property
  • Physical analysis results
  • Visual and petrographic examinations of concrete and rock aggregates
  • Calculation of the Pyrite Swelling Potential Index of the backfill material (IPPG in french)
  • Conclusions and recommendations arising from the results
  • A solution approach in the event of a problematic case.

For a MULTI-DWELLING, COMMERCIAL or INDUSTRIAL building

Contact us for a quote that reflects the unique characteristics of the building

Our Work Process

Components Inspected :

  • Concrete slabs (cracks, heaving, white powder, deterioration)
  • Components supported by the slab (partitions, doors, false floors, etc.)
  • Foundation walls (cracks, displacements)
  • Upper floor (floors, partitions, doors, etc.)
  • Exterior inspection (land slopes, gutters, trees, foundation walls, etc.)
  • Fast coring of concrete slabs (12.7 cm diameter)
  • Manual sampling of backfill at full depth in the basement and 45 cm deep under the garage or ground level slab
  • Sampling of natural soil beneath the backfill in the basement
  • Resulting cavities will be filled with certified crushed stone and quick setting concrete
  • Proper restoration of the premises
  • Tests and analyzes are carried out in compliance with current protocols and standards (BNQ, ASTM, CTQ-M100, CTQ-M200)
  • Visual examination of concrete (general quality, sulfate attack, moisture barrier, etc.)
  • Aggregate particle size analysis
  • Petrographic examination of aggregates (determination of rock types in the backfill)
  • Calculation of the Pyrite Swelling Potential Index of the backfill (IPPG in french)
  • The IPPG is qualified according to the values ​​listed in the following table:
IPPG Swelling Potential
0-10 negligible
11-20 Weak
21-40 Weak to Moderate
41-60 Moderate to High
61-80 High
81-100 Extremely High

Components Inspected :

  • Concrete slabs (cracks, heaving, white powder, deterioration)
  • Components supported by the slab (partitions, doors, false floors, etc.)
  • Foundation walls (cracks, displacements)
  • Upper floor (floors, partitions, doors, etc.)
  • Exterior inspection (land slopes, gutters, trees, foundation walls, etc.)

  • Fast coring of concrete slabs (12.7 cm diameter)
  • Manual sampling of backfill at full depth in the basement and 45 cm deep under the garage or ground level slab
  • Sampling of natural soil beneath the backfill in the basement
  • Resulting cavities will be filled with certified crushed stone and quick setting concrete
  • Proper restoration of the premises

  • Tests and analyzes are carried out in compliance with current protocols and standards (BNQ, ASTM, CTQ-M100, CTQ-M200)
  • Visual examination of concrete (general quality, sulfate attack, moisture barrier, etc.)
  • Aggregate particle size analysis
  • Petrographic examination of aggregates (determination of rock types in the backfill)
  • Calculation of the Pyrite Swelling Potential Index of the backfill (IPPG in french)
  • The IPPG is qualified according to the values ​​listed in the following table:
IPPG Swelling Potential
0-10 negligible
11-20 Weak
21-40 Weak to Moderate
41-60 Moderate to High
61-80 High
81-100 Extremely High

Our Approach

  • Professionals always available to answer your questions
  • Competitive fees and fast turnaround times
  • Expert reports written in layperson’s terms
  • Clear and well laid out conclusions and recommendations
  • Impartiality, integrity and professionalism in all aspects of our work
  • High priority on cleanliness, safety and courtesy at our clients premises

FAQ

The presence of pyrite in rock aggregates used as backfill can lead to problems if exposed to certain conditions. Aggregate particles containing large amounts of pyrite can react with oxygen and water and are likely to expand, crack and crumble over time. This expansion can lead to cracks in the overlying concrete slab. The thrust can even lift it. In garages or other ground level slab building sections, the thrust can also be to the sides and affect the foundation walls.

Essentially, it is a series of tests to assess the quality of the crushed stone used as backfill under the concrete slab. These tests allow the determination of the Pyrite Swelling Potential Index (IPPG in French) which is a number corresponding to the swelling potential of the backfill material. This number ranges from 0 to 100. For example, if the IPPG is between 0 and 10, the swelling potential is negligible. If it is between 80 and 100, the swelling potential is extremely high.

The professional’s judgment is based on several factors that go into the assessment. Generally, it is never based solely on the Pyrite Swelling Potential Index (IPPG). Criteria such as the age of the building as well as the thickness and the sizes of particles are often considered to play down a situation where the IPPG is high. With the knowledge of our staff and the experience gained through case histories, we are able to formulate conclusions that reflect the real situation.

Demand for pyrite testing is generally concentrated in the greater Montreal area since the problematic quarries are mostly located there. The Montérégie (south shore of Montreal) is where most cases are located. Certain areas of Montreal such as Rivière-des-Prairies, Pointe-aux-Trembles and the west of the Island (Pointe-Claire, Dollard-des-Ormeaux, etc.) are also known risk areas. Finally, cases are also found in Laval, in the Basses-Laurentides and Lanaudière (Repentigny, Legardeur, etc.).

No. The result obtained during the pyrite test, the Pyrite Swelling Potential Index (IPPG in French), is calculated according to the types of rock in the backfill and not according to what remains to react in the future. This therefore means that the IPPG will not vary over time. However, the age of the building is a criterion that the professionals at Sedexlab consider when writing the conclusions of the report.

Chemical analysis is another type of test that allows getting a better grasp on the progress of the chemical reaction in the backfill material. This test is complementary to the IPPG and cannot be done alone. It is often called “the 2nd stage”. This additional test will give an estimate of the progress of the pyrite oxidation reaction. Is it just at the beginning? Moderately advanced? Or finishing off? In cases where a chemical analysis is deemed necessary, professionals at Sedexlab will offer it to you as the IPPG results are put out.

Although there is no law requiring a pyrite test to be performed, it is almost always required in cities and towns deemed most at risk, often by buyers, real estate brokers, banks, notaries, or home inspectors. Cracks in the concrete floor are often a good indication of the presence of pyrite, but the absence of cracks does not necessarily mean the absence of pyrite. By performing the pyrite test, you will be informed about the future potential for damage associated with the oxidation of pyrite and you will also be protected against future claims for latent defects.

The number of tests (or samplings) will depend on the layout and size of your home. In the case of an average-sized single-family home without a garage, a single sampling will suffice. An additional sampling will be required if your house has a garage or any other added section with a ground level concrete slab. In short, a sampling is required per level of concrete floor. Also, please contact us for a quotation for larger buildings such as commercial, industrial or multi-unit condo or rental buildings.

Once the backfill sample has been taken, our technicians will fill the hole with certified crushed stone. They will then plug the top of the hole with fast-setting concrete. In the event that there is floor covering, our technicians will put the floor back in place before leaving.