Buyer’s guide

Understanding the defects that keep showing up in inspection reports

One topic per page, written for a buyer: what it is, how the inspector sees it, what it costs, what to do before lifting the condition. Updated September 8, 2026.

01
Pyrite in the backfill: how serious is it, and what does it cost?
Pyrite is a mineral found in some crushed-stone backfill placed under concrete slabs (garage, basement). As it oxidizes in contact with moisture it swells, lifting and cracking the slab. The problem is common in Quebec homes built from the 1970s to the late 1990s, it is measured by a laboratory test, and the fix is to replace the backfill and the slab.
02
Iron ochre: can you buy a house that has it?
Iron ochre is a rust-coloured, jelly-like deposit formed when bacteria transform iron dissolved in groundwater. It gradually clogs the French drain and can lead to basement water infiltration. It cannot be eliminated: it is managed with an accessible drain, cleanout ports and regular maintenance. An affected house can be bought, but knowingly and with the right budget.
03
Vermiculite in the attic: should you worry about asbestos?
Vermiculite is a loose, granular, shiny insulation widely used in attics and walls of homes built before 1990. Much of what was sold in Canada came from a mine whose ore contained asbestos. As long as it is left undisturbed it does not release fibres; it is when you renovate, insulate or drill that it must be tested and, if needed, removed by a specialized contractor.
04
Poly-B plumbing: do you have to replace it all before buying?
Polybutylene (Poly-B) is a grey plastic water pipe installed in many houses and condos between the late 1970s and the mid-1990s. It ages badly: it becomes brittle, cracks and leaks, often without warning. Many insurers refuse to cover water damage or require its replacement. You can buy a house that has it, but budget its replacement and tell your insurer.
05
Federal Pioneer (Stab-Lok) electrical panel: does it need replacing?
Federal Pioneer Stab-Lok panels, very common in Canadian homes from the 1950s to the 1980s, are known for breakers that do not always trip on overload, hence a risk of overheating and fire. Many insurers and inspectors recommend replacement. It is not a hidden defect: the name is on the panel door.
06
Aluminum electrical wiring: danger or simple precaution?
Between roughly 1965 and 1975, copper was expensive and many homes were wired with aluminum. The wire itself is not dangerous; its connections are the issue: aluminum expands, oxidizes and loosens at outlets, switches and splices, which can overheat. The answer is not to rewire everything, but to have every connection checked and secured by a master electrician.
07
Radon: should you test before buying a house?
Radon is a natural radioactive gas, odourless and colourless, that comes from the ground and builds up in basements. Health Canada ranks it as the second leading cause of lung cancer in the country after smoking, and estimates that about 7% of Canadian homes exceed the guideline of 200 becquerels per cubic metre. It cannot be seen or guessed from the neighbourhood: only a test measures it, and a reliable test lasts at least three months.
08
Hidden defects and the legal warranty: what does it really cover?
In Quebec, the seller of a house warrants the buyer against hidden defects: a serious defect, existing at the time of sale, unknown to the buyer and undetectable by a prudent buyer. What the inspector saw and wrote in the report is no longer hidden: that is where the inspection report changes everything. And if the deed says “without legal warranty, at the buyer’s own risk”, that recourse disappears.
09
The inspection condition: how many days, and what can you do with it?
The inspection condition is the clause of the offer to purchase that lets you have the house inspected and, depending on the result, renegotiate or walk away without penalty. In Quebec the usual window is 7 to 10 days after acceptance, sometimes less in a hot market. That window must hold the inspection, reading the report, follow-up checks and, if needed, quotes. It is extended only if the seller agrees in writing.
10
Buying “without legal warranty, at the buyer’s own risk”: what does the clause mean?
This clause removes the hidden-defect recourse the Civil Code normally gives the buyer. It is common in estates, repossessions and sales by owners who never lived in the house. It does not allow the seller to lie: if they knew of a defect and concealed it, the recourse survives. For everything else, the buyer bears the risk. The inspection then becomes the only protection, and the price must reflect the risk.
11
Water heater over 10 years old: should it be replaced before buying?
A tank water heater generally lasts 10 to 12 years. Past that age, the risk of the tank leaking rises quickly, and a failing tank dumps tens of litres on the floor. That is why many insurers require its replacement or exclude water damage from an appliance that is too old. The manufacturing date is on the label: it is the first thing to read.
12
Basement water infiltration: why the grading is often the cause
Most basement infiltration does not come from a defective foundation, but from surface water allowed to pool against the walls: ground sloping toward the house, downspouts discharging at the foundation, flower beds holding water. The usual rule is ground that slopes away from the house by at least 15 cm over the first 3 metres, and downspout extensions carrying water well away from the walls. These are inexpensive fixes, to do before suspecting the drain.
13
What does a pre-purchase inspection not see? The limits to know
A pre-purchase inspection is visual and non-destructive: the inspector examines what is visible and accessible on the day of the visit, without drilling, dismantling or moving heavy furniture. They do not see inside the walls, under the slab, inside the drain, or the roof under snow. What they cannot examine is recorded as a limitation in the report. These limitations are not details: they map what you are buying without knowing it.
14
How to choose a building inspector in Quebec, where the profession is not regulated
In Quebec, anyone can call themselves a building inspector: there is no professional order and no mandatory licence. Protection comes from elsewhere: the OACIQ requires brokers to recommend an inspector who carries professional liability insurance, follows a recognized standard of practice (BNQ 3009-500 is the reference), uses a written service agreement and delivers a written report. Associations such as the AIBQ and the APCHQ require training and insurance from their members. Those four criteria are what to check.
15
French drain: how do you know whether it still works?
The French drain is the perforated pipe laid at the foot of the foundation, which collects groundwater and carries it to the sewer or a sump. It is buried, hence invisible: the inspector cannot judge its condition. The signs are indirect (dampness, efflorescence, a busy pump, ochre deposits), and the only reliable examination is a camera inspection, done by a specialist from a cleanout port. Without a port, one must be created.
16
Humidity and mould in a house: when should you worry?
Health Canada recommends keeping a home’s relative humidity between 30 and 50%. Above that, water condenses on cold surfaces (windows, wall corners, basement) and mould sets in within days. A small patch on a shower joint cleans off; a stain that comes back, a cellar smell or a spreading surface signal a water source to find, not a cleaning problem. The inspector reports what they see and sometimes measures humidity, but does not test for mould.