Yikes! Am I obliged to do Pyrite test?
Pyrite is a big problem when you have it! Repairing it entails digging up the basement and garage, removing the affected gravel backfill and then replacing these materials. This project can cost in the tens of thousands of dollars to undertake, or cost you a hefty reduction on your sale price should you decide to sell without repairing it. Note that pyrite is not hazardous to your health.
First and foremost, what is Pyrite and how does it affect a construction?
Also known as Fool’s Gold due to it’s yellow sheen, pyrite is an iron sulfide found in quartz veins, sedimentary rock and metamorphic rock. In Quebec in the mid-1900s, gravel that contained pyrite was used to line building foundations under the concrete slabs of basements and garages. Unbeknownst to builders at the time, the chemical reaction of pyrite with water and oxygen activates the swelling process of the mineral causing any concrete slab laying over the gravel to crack under the rising pressure.
High risk pyrite areas of Quebec
Generally, the entire Saint-Lawrence Valley is considered a risk zone. Specific areas have been pointed out as being especially vulnerable like the West-Island and the South-Shore of Montreal. Your real estate broker will know better if you are at risk as we hacew ample knowledge of local housing stocks.
What are the symptoms of Pyrite?
Pyrite can lay dormant for many years if it has not been exposed to moisture and air which means that sometimes there can be no symptoms at all. Ultimately a test of the gravel below the concrete slab is the only way of knowing 100% what your home’s pyrite level is. Visible markers of a basement or garage that have been affected by pyrite include:
cracks in the concrete floors or in finished walls
raised portions of the concrete slab
doors and window frame movement
What to do if you plan on selling your home and you are in a risk zone?
Anyone selling a property in the pyrite risk zone is required to tell buyers the levels of pyrite found in their basement and garage. Laws governing this requirement are not clear and pyrite tests can sometimes be delayed until the buyer requests the test be done during the offer process. Because the results are expected from the start, the seller is usually the one paying for this test (however whether the buyer or the seller pays for it can still be negotiated between the parties). Once a test has been performed, the law is clear that the results must be disclosed to potential buyers.
What are the amounts of pyrite that pose a danger to structures or lower the resale value?
First of all, a pyrite test will return a report with an IPPG number between 0 and 100 where 0 is no pyrite and 100 is extremely high levels. IPPG stands for Indice pétrographique du potentiel de gonflement which translates to Petrographic index of swelling potential. IPPG levels below 30 are considered a low risk of swelling potential however it is always best to consult a foundation specialist once you have received your results. Here are the levels and their associated risk:
0-10 IPPG = Negligible risk
11-20 IPPG = Low risk
21-40 IPPG = Low to medium risk
41-60 IPPG = Medium to high risk
61-80 IPPG = High risk
81-100 IPPG = Extremely high risk
How is a pyrite test performed?
The technicians will arrive with equipment that drills a hole 6 inches in diameter into the slab of your basement and/or garage. They will try and drill through exposed concrete to avoid damage to your floor finishing but it is not always possible. An investigation of the plumbing system of the property will determine where they can drill as they will want to avoid any possibility of damaging underground pipes. Once they drill through the slab, a sample of the gravel below will be taken and the technicians will seal the opening with concrete. Extracting a sample for a pyrite test takes a couple of hours for the technicians to perform and results can be received the following day. Full official reports can take up to 2 weeks to receive.
If you have any more questions about pyrite like how to price your home or if you are looking at a home with pyrite issues, please contact me through the form below.