Assess the presence and/or extent of pyrite issues
Problem related to the swelling of pyrite
"Pyrite problems" are related to the swelling of certain granular fill material used in residential construction. Pyrite is an iron sulphide found in several rock formations, including shale, a soft sedimentary rock resembling clay, sometimes used as a backfill under the slabs on grade of basements or garages.
Under certain humid and oxygenated conditions, the pyrite oxidizes, causing swelling of the fill material which can lift and break the concrete slab. The ensuing sulphation can also attack the concrete slab. "Pyrite problems" can appear decades after the construction of a house.
In Quebec, the phenomenon is widespread on the south shore of Montreal or in the Rivière-des-Prairies district. It is also found around the St. Lawrence Valley, mainly in buildings constructed during the 1980s.
Since April 1999, manufacturers have now applied the CTQ-M100 standard, which certifies the quality of granular fill material placed underneath concrete slabs on grade. Owners must require that the contractor carrying out the construction work provides the original delivery slip confirming that the crushed stone and/or granular fill material used is certified "DB".
Owners who want to carry out a "pyrite test" must hire a laboratory recognized by the Association des firmes de génie-Conseil (AFG) that apply the CTQ-M200 standard. SOLROC is accredited by the AFG (Association des firmes de génie-Conseil) to assess the presence and/or extent of pyrite issues.