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SEDEXLAB inc.

724, Bériault, suite B,
Longueuil (Québec) J4G 1R8

1250, av. de la Station, casier 6
Shawinigan, Qc
G9N 8K9

François Hamel, Géo.

Directeur

fhamel@sedexlab.com

Pascal Fortin, Géo.

Chargé de Projet

pfortin@sedexlab.com

Write to us

Technical survey:

Our work process

As specified bellow, the survey includes three distinct stages:

01

Visual
survey

Objective :

To confirm the presence or the absence of distinctive signs of pyrite associated swellings.

Elements inspected :

  • Concrete slabs (cracks, heaving, white sulphates, deterioration)
  • Elements resting against the concrete floor (drywall, doors, false floors, etc.)
  • Foundation walls (cracks, movements)
  • Upstairs (floor, partition walls, doors, etc.)
  • Exterior survey (slopes, gutters, trees, foundation walls, etc.)

Following a careful visual examination of the property, the professional is able to confirm the presence or the absence of characteristic signs related to the swelling of the backfill underneath the concrete slabs. Other information may be collected through interviews with the owner or his (her) representatives.

02

Materials
sampling

Objective :

To determine the conditions and the thickness of the materials encountered and sampled for later analyses (concrete, backfill and soils).

  • Rapid drilling of the concrete floor (15 cm diameter)

  • Manual sampling of the backfill all the way down to the natural underlying soil in the basement sections and down to a depth of 45 cm underneath ground level concrete floors such as garages.

  • Sampling of the natural underlying soil in the basement.

  • Filling of the cavity with certified crushed stone before re-sealing with a quick setting concrete.

Note that we take great care in respecting our working environment. That is why our technical personnel has been trained to use work methods that are based on cleanliness and courtesy. Be assured that the equipment used is dust and pollution free.

03

Laboratory
analyses

Objective :

Identifying the type of material underneath the concrete slabs and to determine its swelling potential. The analyses also allows to characterize the concrete and the natural soils.

  • Examination of the concrete (general quality, sulphation deterioration, polyethylene, etc.)

  • Granulometric examination of the backfill (calibre separation)

  • Petrographic examination (rock type identification)

The essays allow our geologists to identify the type of backfill and its swelling potential. An index (a whole number) is used for measuring the materials swelling potential. This index called PSPI (petrographic swelling potential index), lies between 0 and 100, depending on the quality of the material. The PSPI is qualified according to the values of the following table.

PSPI Swelling potential

  • 0-10 Negligible
  • 11-20 Low
  • 21-40 Low to intermediate
  • 41-60 Intermediate to high
  • 61-80 High
  • 81-100 Extremely high

Note that a high swelling index is not necessarily synonymous of a problem.

The professional’s opinion is based on many factors. Generally, the swelling index is not the only factor considered. Criteria such as the age of the building, the thickness and the calibre of the backfill will often intervene in order to temper a situation where the PSPI is high. Thanks to the knowledge of our personnel and our experience acquired with case history, we are able to issue conclusions that reflect reality.

All the data collected on the sampling site and in the laboratory is included in a complete report, written in compliance with the CTQ-M200 protocol developed by the Comité technique québécois d’étude des problèmes de gonflement associés à la pyrite (Quebec technical comity for the study of pyrite associated swelling problems).

Report content

The survey report is devised in two main sections :

The annex includes all the data collected on site and in the laboratory. Tables and schemes are used to present the information.

The summary gathers all the relevant information in a clear and concise text where the professional’s opinion on the materials swelling potential is formulated. The professional will also offer solutions and prevention measures in problem cases.

A non-jargon read

The conclusions are stated in a clear and concise text in which the on-site and laboratory data are reported in accessibly to the untrained reader.

Note that a high swelling index is not necessarily synonymous of a problem

The professionals’ opinion is based on many factors. Generally, the swelling index is not the only factor considered. Criteria such as the age of the building, the thickness and the calibre of the backfill will often intervene in order to temper a situation where the PSPI is high. Thanks to the knowledge of our personnel and our experience acquired with case history, we are able to issue conclusions that reflect reality.

Professional liability insurance

Note that all our reports are backed by professional liability insurance, which protects you in the event of the sale or transfer of your property. The report is also a requirement, should you be eligible for the governmental subsidy intended for owners stricken by a pyrite swelling problem.

A sale? Governmental subsidy?

Here are the benefits of proceeding with the evaluation of the swelling potential of the backfill material underneath the concrete floor of your property.

  • The survey will protect you in the event of legal proceedings for hidden defect and/or damages intended against you in the case of the sale or transfer of your property.
  • The evaluation is also a requirement, should you be eligible for the governmental subsidy intended for owners stricken with pyrite associated swelling problems.
  • It allows a better real estate appraisal of the property, witch will influence the amount of taxes you pay.
  • It gives a potential buyer or lender a better idea of the real value of the property.

For more information on the governmental assistance program for owners, click here.

Our laboratory

The reports and analyses are done in compliance with the regulations and protocols in effect (BNQ, ASTM, ISO, CTQ-M100, CTQ-M200) and respect all professional ethical and confidentiality codes.

The quality assurance system combined with adequate work spaces as well as technologically advanced equipment, allow us to offer our clients the guarantee of reliable and rigorous results within established deadlines.