Does the GCR Warranty Cover Radon in a New Home in Quebec?

Flat-vector illustration of a new house beside a warranty certificate — GCR new-home warranty and radon in Quebec

Short answer: No. The mandatory warranty plan administered by the Garantie de construction résidentielle (GCR) does not mention radon anywhere and does not cover it as a named defect. The regulation that governs the warranty (B-1.1, r. 8) does not contain the word "radon." Unlike Ontario, where the Tarion warranty explicitly provides up to $50,000 for radon mitigation over a 7-year window, Quebec has no equivalent warranty protection specifically dedicated to radon. The only way to know the level in your new home is still to run an alpha-track test of at least 91 days.

This article carefully separates two things that are often confused: (1) the warranty plan (what it reimburses or repairs, and for how long) and (2) the Building Code requirements (the passive pipe or column beneath the slab). They are not the same thing, and only the second one directly targets radon.

Important notice: This article is informational and does not constitute legal advice. For your specific situation, contact the GCR directly (garantiegcr.com).

What Is the GCR and What Does It Cover?

The Garantie de construction résidentielle (GCR) is the body that administers Quebec's mandatory warranty plan for new residential buildings. Any contractor who builds a covered new home (single-family detached, semi-detached, row house, or certain condominium buildings of four storeys or fewer) must enroll in it. The warranty is governed by a provincial regulation, the Regulation respecting the guarantee plan for new residential buildings (B-1.1, r. 8), which sets out precisely what is covered and for how long.

For a single-family home, section 10 of the regulation provides that, after acceptance of the building, the warranty covers:

Protection category Reference (Civil Code) Window to make a claim
Completion of the work s. 10 (1°) Reported in writing at acceptance (or within 3 days if not yet moved in)
Apparent defects and poor workmanship art. 2111 C.C.Q. Reported at acceptance (or within 3 days)
Non-apparent poor workmanship art. 2113 and 2120 C.C.Q. Discovered within one year of acceptance
Latent defects art. 1726 or 2103 C.C.Q. Discovered within 3 years of acceptance
Defects in design, construction or production, and soil defects art. 2118 C.C.Q. Appearing within 5 years of the end of the work

The warranty also covers, under certain conditions, relocation, moving, and storage of belongings during corrective work, as well as restoration of the building. The amounts are capped per address: $50,000 for deposits, $6,000 for relocation and storage, and the contract amount — never exceeding $300,000 — for completion and for the repair of defects and poor workmanship (section 13 of the regulation, amounts indexed annually).

This is a robust regime for classic construction defects (foundation, roofing, weatherproofing, structure). But none of these categories names radon.

The Honest Answer on Radon

Regulation B-1.1, r. 8 does not contain the word "radon." Nowhere in the entire text is there any mention of radon, indoor air quality, or an underground gas as a covered defect. In other words, there is no named warranty coverage for radon in Quebec, unlike in Ontario.

This raises a legitimate question: could a high radon level still fall under an existing category — poor workmanship, a latent defect, or a construction defect? The honest answer is: it is uncertain, and it is not guaranteed.

  • Radon is not a defect of material or finish: it is a natural gas that comes from the soil. Fitting it into the definition of "poor workmanship" would be difficult.
  • For it to be a latent defect (art. 1726 C.C.Q.) or a construction defect (art. 2118 C.C.Q.), you would have to demonstrate that the home has a design or construction defect serious enough — for example, a slab or an anti-radon system that does not conform to accepted practice or to a standard in force — and that this defect makes the building unfit for its intended use or seriously reduces its usefulness. The mere fact that a code-compliant home shows a high radon level does not, on its own, establish a construction defect.
  • The regulation expressly excludes "the repair of damage resulting from contaminated soil, including the replacement of the soil itself" (section 12, paragraph 7°). An argument based on "soil contamination" would therefore run directly into an exclusion — and that particular exclusion is not neutralized by the clause that restores coverage where the contractor failed to follow accepted practice.

In practice, the most plausible route would be to argue a design or construction defect tied to an anti-radon system that was poorly executed or non-compliant with the Code, within the 5-year window. But nothing in the regulation guarantees the outcome, and radon is never named in it. Do not rely on the warranty plan to protect you against radon.

GCR Construction Standard vs. Warranty Coverage: Don't Confuse Them

A common point of confusion is the belief that the GCR has "added radon to its warranty." That is not the case, and it helps to separate the body's two distinct roles.

  1. The warranty plan (what we just discussed): it reimburses or repairs specific defects. Radon is not on the list.
  2. The technical documentation the GCR publishes to help contractors comply with the Quebec Building Code. In November 2025, the GCR updated a technical fiche on protection against underground gases — radon (fiche FT-9.13.4, version 02, dated November 6, 2025), which explains, among other things, the requirement for a passive extraction column.

This fiche does not create new warranty coverage. It documents a requirement that comes from the Building Code, not from the warranty regulation. If you have read elsewhere that "the GCR added a complete passive-column standard in November 2025," that is a description of this documentary update of a Code requirement — not the addition of financial protection for radon in the warranty plan. The distinction is crucial: having a compliant passive column does not mean you are compensated if your home shows a high radon level.

The Quebec Building Code: The Passive Column or Pipe Beneath the Slab

This is where radon is actually regulated in Quebec — through the Building Code, not through the warranty.

The Dates, Verified at the Source

The dates circulating online are contradictory. Here is the timeline established from the official sources of the Régie du bâtiment du Québec (RBQ):

  • January 8, 2022 — coming into force of the new Chapter I, Building, of the Quebec Construction Code (based on the 2015 NBC), which introduces the protection measures against underground gases, including radon.
  • June 2, 2022 — coming into force of an inter-edition published in the Gazette officielle du Québec on May 18, 2022. It extends the scope of the measures to the entire territory of Quebec by removing the notion of "recognized risk zones," following recommendations from public health authorities and Health Canada.
  • July 8, 2023 — end of the transition period. Until that date, buildings constructed or transformed since January 8, 2022, could comply with either the old or the new edition of the chapter.

In plain terms: the requirement has existed since January 8, 2022, became province-wide on June 2, 2022, and the period in which the old Code remained permitted ended on July 8, 2023. (A reference to "June 2023" that sometimes appears is an imprecise approximation of this end of transition, which is actually July 8, 2023.)

What the Code Requires

The provisions aim to build in, from the construction stage, the infrastructure needed for eventual radon mitigation. Depending on the requirements, this notably includes:

  • a layer of clean granular material beneath the slab and a pipe of at least 100 mm (4 in.) in diameter connected below the slab;
  • in many cases, a complete passive extraction column — no longer simply a "rough-in" pipe left waiting — that runs vertically through the building and discharges above the roof, at least 10 ft. from windows, doors, and air intakes;
  • precise technical criteria (a pipe with no perforations, compliant materials such as PVC series 40, insulation of unheated sections) and mandatory labelling of the pipe with stickers, to avoid any confusion with other systems.

These requirements make Quebec a Canadian frontrunner, ahead of the gradual adoption of the 2025 Construction Code in other provinces.

For a detailed explanation of these requirements, see the sibling article: Quebec Building Code and radon.

Why the Mandatory Pipe Doesn't Guarantee a Low Radon Level

Here is the most important point for a new-home owner, and the one the warranty/Code confusion most often hides.

A passive column or pipe is not protection in itself. It is a passive system: it prepares the home for future mitigation, but it does not guarantee that the radon level will be below the guideline. If a test reveals a high level, the system must be activated — that is, a fan is added to create active depressurization beneath the slab. Without that activation, the passive column may reduce radon in some homes, but nothing assures it will in yours.

It is also worth restating Health Canada's position: there is no radon level free of risk. The 200 Bq/m³ threshold is a guideline (an action level), not a line between harmless and harmful. Below that threshold the risk is lower, but it is never zero.

The practical consequence: whether your new home has a passive pipe, a complete column, or a system that is already activated, you will only know its true level by testing it. To learn more about radon in new construction in Canada, see Radon in new construction homes in Canada and our guide to Canadian building codes and radon.

What a New-Home Owner Should Do: Test

The only way to know whether radon is a problem in your new home is to run a long-term alpha-track test, lasting a minimum of 91 days, ideally during the heating season (fall through spring), on the lowest level you occupy regularly.

Recommended steps:

  1. Test as soon as possible after taking possession, using a long-term kit (≥ 91 days).
  2. If the result is below 200 Bq/m³, the risk is lower — but since no level is free of risk, consider retesting periodically (for example every 5 years, or after renovations that change the airtightness or ventilation).
  3. If the result is at or above 200 Bq/m³, move to mitigation: the existing passive system is activated (adding a fan), or an active sub-slab depressurization system is installed, designed by a C-NRPP-certified professional. See: What to do if your radon level is above 200 Bq/m³ and How radon mitigation works in Canada.

For regional radon data on Quebec, see our regional file: Radon in Quebec.

For anglophone homeowners across the West Island, the Eastern Townships (Estrie), the Outaouais, and the rest of the province, the test method is the same: a long-term kit, not a quick weekend reading. A natural in-context option here is the RadonTest.ca radon test kit, a long-term alpha-track kit (91 days and up), analyzed by a C-NRPP-certified laboratory, with prepaid return shipping and analysis in Canada. It is precisely the type of test required for an Ontario warranty claim, and the only type that gives a reliable estimate of your annual average.

The Contrast with Ontario: The Tarion Warranty Does Cover Radon

The contrast with Ontario is striking and illustrates the absence of any equivalent in Quebec.

In Ontario, the mandatory new-home warranty is administered by Tarion. According to Tarion's official site, the builder warranty includes up to $50,000 for radon mitigation when levels exceed the Health Canada guideline, and this coverage lasts for the full 7-year warranty period. Tarion notes that Ontario is one of the only jurisdictions in Canada to cover radon mitigation in its statutory new-home warranty. The conditions:

  • the test result must exceed 200 Bq/m³;
  • the test must run for at least three months;
  • the kit or professional used must be certified by the National Radon Proficiency Program (C-NRPP);
  • the builder must then carry out the corrective work (typically the installation of a mitigation system), failing which Tarion steps in.
Quebec — GCR Warranty Ontario — Tarion
Is radon named in the warranty? No (absent from regulation B-1.1, r. 8) Yes (policy published by Tarion)
Financial coverage for radon No named protection Up to $50,000
Duration N/A for radon (construction defects: 5 years) 7 years
Trigger No radon threshold provided Test > 200 Bq/m³
Required test N/A C-NRPP-certified test, ≥ 3 months
Construction requirement (Code) Passive column / pipe mandatory (since 2022) Per the Ontario Building Code

In other words: Quebec relies on prevention at the construction stage (the mandatory passive pipe), while Ontario adds financial protection after the fact (the Tarion warranty). A Quebec buyer must therefore be aware that they do not benefit from the same financial safety net.

For the details of the Ontario procedure, see our Tarion radon warranty claim guide, and for an overview, does your new-home warranty cover radon: a province-by-province guide.

How Much Does Activating or Mitigating Radon Cost?

If your test reveals a high level, the cost depends on the state of your home.

  • Activating an existing passive column (adding a fan to a system already installed in line with the Code) is generally the least expensive option, since the infrastructure is already in place.
  • Installing a complete active sub-slab depressurization system (where there is no usable column) typically costs on the order of $2,000 to $4,000 in Canada, depending on the home's configuration, the foundation type, and the complexity of the routing. Some more complex cases cost more.

This is precisely why the Quebec Code now requires the passive infrastructure from the construction stage: a home already fitted with a complete column will generally be cheaper to bring into compliance than a home where everything still has to be done. To understand how a system works and what its components are, see How radon mitigation works in Canada.

Radon is not only a new-construction issue, and it is not only a single-family-home issue. If you want to understand the broader picture of Quebec's requirements for shared and institutional buildings, see our sibling article on radon in schools and daycares in Quebec.

Frequently Asked Questions

Does the GCR cover radon in a new home in Quebec? No. The regulation that governs the GCR warranty (B-1.1, r. 8) does not mention radon and provides no named coverage for it. Unlike Tarion in Ontario, the Quebec warranty plan offers no dedicated financial protection against radon.

Can a high radon level be claimed as a latent defect or a construction defect in Quebec? It is not guaranteed. You would have to demonstrate a design or construction defect (for example, an anti-radon system that does not conform to the Code), within the 5-year window provided by section 2118 of the Civil Code. In addition, an argument based on "soil contamination" would run into the express exclusion in section 12 (7°) of the regulation. Consult a lawyer for your specific situation.

Did the GCR add a radon standard in November 2025? In November 2025, the GCR updated a technical fiche (FT-9.13.4) explaining the requirement for a passive extraction column. This is documentation about a Building Code requirement, not an addition of coverage in the warranty plan.

Since when has the anti-radon pipe been mandatory in new homes in Quebec? Since January 8, 2022 (coming into force of the new Chapter I, Building). The requirement became province-wide on June 2, 2022 (removal of the "risk zones"), and the transition period ended on July 8, 2023.

Is a passive column enough to protect my home against radon? No. It is a passive system that prepares for future mitigation; it often must be activated by adding a fan if a test reveals a high level. And according to Health Canada, no radon level is free of risk — the 200 Bq/m³ threshold is an action guideline.

How should I test my new home? With a long-term (≥ 91 days) alpha-track test, preferably during the heating season, on the lowest level you occupy regularly. This is the only reliable method for estimating your annual average.

What should I do if my test exceeds 200 Bq/m³? Proceed to mitigation: activation of the existing passive system, or installation of an active sub-slab depressurization system, by a C-NRPP-certified professional. See What to do if your radon level is above 200 Bq/m³.

Order your radon test kit → — all-in, analyzed in Canada, prepaid return shipping.

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