Latent vs Patent Defects in Ontario: Who Pays for Hidden Problems?
Caveat emptor, seller liability, Tarion warranties, and the two-year limitation clock
The scenario is familiar to any real estate litigator. Months after closing, a renovation opens a wall and reveals rotted framing, mould, or a foundation crack that has clearly been leaking for years. The buyer's first question is almost always the same:
“The seller must have known about this. Can I make them pay for it?”
The honest answer is: it depends on three things. First, whether the defect is classified as patent or latent. Second, what the seller knew and did — concealment and misrepresentation are treated very differently from mere silence. Third, who the right defendant actually is, because in many cases the stronger claim is not against the seller at all, but against a builder, contractor, or home inspector.
This article explains how Ontario law allocates the cost of hidden problems, what evidence decides these cases, and how to think about the economics before starting a lawsuit.
What Is a Patent Defect? What Is a Latent Defect?
The entire allocation of risk turns on this classification, so it is worth being precise.
Patent Defect
A defect discoverable by an ordinary purchaser — or their home inspector — through a reasonable inspection of the property. Examples:
- A visible water stain on a ceiling
- A cracked windowpane or sagging deck
- Worn shingles visible from the street
- A damp smell in an unfinished basement
- Obvious sloping floors
Latent Defect
A defect that a reasonable inspection would not reveal. Examples:
- A foundation crack behind finished basement drywall
- Mould inside wall cavities
- A buried, decommissioned oil tank
- Chronic seepage concealed by fresh paint
- Structural rot under intact flooring
The classification is fact-driven, not fixed. A foundation crack in an unfinished basement is usually patent; the same crack behind a newly finished wall is latent. Finishing work done shortly before listing is therefore often the first thing a court scrutinizes, because it can convert an obvious problem into a hidden one — and, if done to hide the problem, can convert the seller's silence into concealment.
Caveat Emptor: The Default Rule for Resale Homes
Ontario law starts from caveat emptor — let the buyer beware. For resale residential property, the buyer takes the property as it is, subject to the terms of the Agreement of Purchase and Sale. The law expects buyers to protect themselves through inspection, conditions, and contractual warranties negotiated before closing, not through litigation afterward.
Two practical consequences follow. First, a seller generally has no duty to volunteer information about patent defects. If the ceiling stain was there to be seen and the buyer did not look, the loss stays with the buyer. Second, an “as is” clause in the agreement reinforces the default rule and makes post-closing claims harder, though it does not protect a seller who committed fraud.
But caveat emptor has never been absolute. The Ontario Court of Appeal's decision in McGrath v. MacLean (1979) remains the classic statement of its limits: a seller may be liable for latent defects in defined circumstances involving knowledge, concealment, or misrepresentation. Those exceptions are where nearly every hidden-defect lawsuit is fought.
When the Seller Pays: The Recognized Exceptions
A buyer suing a seller over a latent defect generally must bring the case within one of the following categories.
1. Fraudulent Concealment
A seller who takes active steps to hide a latent defect is liable for it. Painting over recurring water stains days before listing, panelling over a cracked foundation wall, or stacking storage boxes to block sight of damage are the recurring fact patterns. The distinction that matters: silence about a defect is usually permitted; active hiding is not. Proving concealment is an evidentiary exercise — the age of the paint or drywall, invoices from prior trades, and the seller's own repair history often decide it.
2. Misrepresentation
A seller who makes a false statement about the property — in answer to a direct question, in the listing, or in a disclosure document — can be liable when the buyer relies on it. A fraudulent or reckless misrepresentation grounds a claim for damages; even an innocent misrepresentation can support rescission in limited circumstances. Half-truths count: disclosing that a basement “had a leak once, fully repaired” when the leak recurs every spring is a misrepresentation, not a disclosure. Where the deception is deliberate, the claim overlaps with our real estate fraud practice.
3. Defects That Make the Home Unfit or Dangerous
A seller who knows of a latent defect that renders the premises unfit for habitation, or dangerous, has a duty to disclose it. Serious structural instability, hazardous environmental contamination, and concealed conditions posing a fire or health risk fall in this category. The threshold is high — ordinary wear, dated wiring, or a damp corner will not meet it — but where it applies, the seller's silence itself becomes the wrong.
4. Statements in an SPIS
The Seller Property Information Statement is an optional form in which sellers answer questions about moisture, structural, and mechanical issues. No seller is obliged to complete one — and many decline precisely because of the litigation risk. But once completed and delivered, the SPIS's answers can be treated as representations. An inaccurate answer can revive a claim that caveat emptor would otherwise bar. If a hidden defect surfaces, the SPIS, the listing, and all pre-closing correspondence are the first documents to pull.
New Homes: Tarion and the Statutory Warranty
Caveat emptor is a resale doctrine. Newly built homes purchased from a registered builder are covered by the statutory warranty scheme under the Ontario New Home Warranties Plan Act, administered by Tarion. The core coverage is tiered:
- One year — defects in work and materials, and protection against unauthorized substitutions
- Two years — water penetration through the building envelope, and defects in electrical, plumbing, and heating delivery and distribution systems
- Seven years — major structural defects
The scheme also protects deposits and compensates certain delayed closings. The trap for owners is procedural: each coverage tier has strict claim-submission windows, and missing a window can forfeit coverage regardless of how serious the defect is. Warranty claims proceed through Tarion's process, with disputes going to the Licence Appeal Tribunal — a different track from a court action against the builder, and the two must be coordinated deliberately.
A statutory warranty claim does not always exhaust the remedies. Where a builder's defective work causes losses beyond warranty coverage, a negligence or breach of contract action may run in parallel — a frequent scenario in our construction litigation practice.
Claims Against Contractors and Home Inspectors
Renovation Contractors
Where the hidden problem traces to renovation work — a botched waterproofing job, structural alterations done without permits, improper drainage grading — the claim against the contractor sounds in breach of contract and negligence. These cases are won and lost on expert evidence about the standard of work, as our analysis of a contractor's courtroom win shows: how expert evidence decided an Ontario construction dispute. Note that the Construction Act lien regime deals with payment, not quality — a defect claim is typically advanced as a counterclaim, set-off, or standalone action.
Home Inspectors
If a defect was patent — discoverable on reasonable inspection — and the inspector missed it, the buyer's recourse may be against the inspector in negligence and breach of contract. Two realities temper these claims. First, inspections are visual and non-invasive by their terms; an inspector is not liable for what was genuinely hidden. Second, standard inspection agreements often contain limitation-of-liability clauses, sometimes capping recovery at the inspection fee. Courts assess those clauses on their wording and the circumstances of signing, and they are frequently — though not always — enforced. An inspector claim is rarely the whole answer, but it can be a meaningful part of a multi-defendant strategy.
The Two-Year Clock and Discoverability
Under section 4 of the Limitations Act, 2002, a claim must be started within two years of the day it was discovered. For latent defects, the discoverability rules in section 5 do the real work: the clock starts when the buyer first knew — or a reasonable person in their position ought to have known — that the damage occurred, that it was caused by an act or omission of the defendant, and that a court proceeding was an appropriate way to address it.
Two consequences matter in practice. A defect discovered four years after closing can still be sued on, because the clock did not start at closing. But a buyer who noticed damp drywall in year one and did nothing may find the clock started then, not when the wall was finally opened in year three. Courts ask what a reasonable owner would have investigated, not what this owner chose to ignore.
The statute also imposes an ultimate limitation period of fifteen years from the day the act or omission took place, regardless of discovery. The operational rule is simple: the day a hidden problem surfaces, start investigating and get advice — the limitation analysis is fact-specific, and waiting is the one strategy that only ever makes it worse.
Evidence: What to Do When You Find the Problem
Latent defect cases are decided on physical evidence and documents. The steps taken in the first weeks after discovery often determine whether the claim is provable at all.
- Photograph and video everything before any repair. Capture the defect, its surroundings, and anything suggesting prior patching or painting.
- Preserve removed materials. Keep sections of mouldy drywall, corroded pipe, or rotted framing. Discarded evidence cannot be examined by anyone's expert.
- Retain a qualified expert early. A structural engineer or building-science consultant should report on the cause and, critically, the age of the defect. Age is often the bridge to proving the seller knew.
- Obtain written repair quotes. Two or three quotes establish the quantum of the claim and support any urgent mitigation work.
- Assemble the transaction file. The Agreement of Purchase and Sale, any SPIS, the listing and its photographs, the inspection report, and all correspondence with the seller and agents.
- Canvass neighbours and prior trades. Evidence that the seller had the same problem repaired before listing is frequently the strongest proof of knowledge.
- Mitigate, but document. You are entitled — and expected — to stop ongoing damage. Do urgent repairs, keep every invoice, and photograph the condition before and after.
The single most common mistake is completing a full repair before anyone independent has documented the defect. Once the wall is rebuilt, the defendant's expert will say the problem cannot be verified — and the court may agree.
Litigation or Negotiation: The Economics of a Defect Claim
Repair cost drives forum, and forum drives cost. In Ontario:
- Up to $35,000 — Small Claims Court: streamlined procedure, limited cost exposure, realistic for self-contained defect claims.
- $35,000 to $200,000 — the simplified procedure under Rule 76 of the Rules of Civil Procedure: capped discovery and shorter trials, where most serious residential defect claims land.
- Above $200,000 — the ordinary procedure, with full discovery and correspondingly higher cost.
The sequence that resolves most cases without trial: a demand letter supported by an expert report and quotes, an exchange of positions, then mediation or direct negotiation. Litigation to judgment makes sense when the damages are substantial, the evidence of knowledge or concealment is strong, and the defendant can pay. It makes less sense when expert fees and the risk of an adverse costs award approach the value of the repair. An unsuccessful plaintiff in Ontario generally contributes to the winner's legal costs — a factor that must be priced in before, not after, issuing a claim. For a fuller breakdown of what a lawsuit costs, see our guide to litigation fees in Toronto.
Defect claims also intersect with failed transactions: a buyer who discovers a serious problem between firm agreement and closing faces a different, time-critical analysis, which we cover in when a real estate deal falls apart in Ontario.
How Starkman & Zhang Lawyers Handles Defect Claims
Our firm litigates hidden-defect disputes from every side of the table — buyers pursuing sellers and builders, owners pursuing contractors, and sellers and trades defending claims. With more than 30 years of Ontario trial experience and decisions verifiable on CanLII, our work in these cases is concentrated in three practices:
Real Estate Litigation
Latent defect claims, misrepresentation, SPIS disputes, failed closings
Construction Litigation
Builder and contractor defect claims, expert evidence, liens and set-off
Real Estate Fraud
Fraudulent concealment, deliberate misrepresentation, tracing and recovery
Our recent court decisions include publicly reported real estate and construction outcomes across Ontario courts.
Frequently Asked Questions
Who pays for hidden defects found after closing in Ontario?
By default, the buyer. Under caveat emptor, a buyer of a resale home bears the risk of defects they could have found through reasonable inspection. The seller pays only in limited circumstances: where the seller knew of a latent defect and actively concealed it, made a false or reckless representation about the property, or knew of a latent defect that rendered the home unfit for habitation or dangerous. For new homes, the builder is responsible under the statutory warranty administered by Tarion. Renovation contractors and home inspectors can also be liable where their own work or reporting fell below the applicable standard.
Can I sue the seller if I find mould or a leaking foundation after closing?
Only if you can establish one of the recognized exceptions to caveat emptor. You must show the defect was latent — not discoverable on reasonable inspection — and that the seller knew about it and concealed it, misrepresented it, or knew it made the home unfit or dangerous. Evidence of knowledge often comes from the physical repair history itself: fresh paint over water stains, patched drywall in front of a foundation crack, prior repair invoices, or statements from neighbours or previous trades. An expert report on the age and cause of the defect is usually central to proving the seller must have known.
Does a home inspection eliminate my claim against the seller?
No, but it changes its shape. Defects your inspector found, or reasonably should have found, are patent defects and remain your risk under caveat emptor. A pre-closing inspection does not bar a claim for a genuinely latent defect that no reasonable inspection would have revealed. If the inspector missed something a competent inspector should have caught, you may have a separate negligence claim against the inspector — though standard inspection contracts often contain clauses limiting liability, sometimes to the amount of the inspection fee, and courts examine those clauses on their specific wording.
How long do I have to sue for a latent defect in Ontario?
The basic limitation period under the Limitations Act, 2002 is two years, but for latent defects the clock generally starts on discoverability — the day you knew, or a reasonable person ought to have known, that the damage occurred, that it was caused by an act or omission of the defendant, and that a proceeding was an appropriate remedy. That may be years after closing. There is also an ultimate limitation period of fifteen years from the day the act or omission took place. Once signs of a problem appear, investigate promptly: ignoring early symptoms can start the clock running against you.
What is an SPIS and does it help my claim?
A Seller Property Information Statement is an optional disclosure form in which the seller answers questions about the property, including known water, structural, and moisture problems. Sellers are not required to complete one, and many decline. But once a seller completes and delivers an SPIS, its statements can be treated as representations to the buyer. An inaccurate or misleading answer can ground a misrepresentation claim that would otherwise be barred by caveat emptor, which makes the SPIS one of the first documents to review when a hidden defect surfaces.
Is it worth suing over a $30,000 repair bill?
Often, but forum choice drives the economics. A claim up to $35,000 can proceed in Small Claims Court, where procedure is streamlined and cost exposure is modest. Claims between $35,000 and $200,000 use the simplified procedure under Rule 76 of the Rules of Civil Procedure, which limits discovery and trial length. Above $200,000, the ordinary procedure applies. In every tier, a documented demand letter supported by an expert report and repair quotes resolves many defect claims without trial, and settlement discussions should be weighed against expert fees, legal costs, and the adverse-costs risk of losing.
References & Resources
- Limitations Act, 2002 (Ontario) — Basic two-year period, discoverability, and the fifteen-year ultimate limitation
- Ontario New Home Warranties Plan Act — Statutory warranty scheme for newly built homes
- Tarion — Administrator of Ontario's new home warranty program
- Rules of Civil Procedure — Rule 76 simplified procedure for claims up to $200,000
- CanLII — Free public access to Canadian court decisions, including latent defect case law
Disclaimer: This article is provided for general informational purposes only and does not constitute legal advice. Every legal matter is unique, and the outcome depends on the specific facts and circumstances of your case. If you are facing a legal issue, please contact a qualified litigation lawyer to discuss your situation. Nothing in this article creates a solicitor-client relationship between you and Starkman & Zhang Lawyers.
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About the Author
Calvin Zhang
Commercial Litigation Lawyer · Starkman & Zhang Lawyers
Handles Ontario real estate litigation — failed closings, deposit forfeitures, misrepresentation claims, and title disputes before the Superior Court.
Found a Hidden Defect After Closing?
Contact Starkman & Zhang Lawyers at 905-477-3110 for a consultation. We assess the classification, the evidence of knowledge, and the economics before recommending a course — in English, Mandarin, or Cantonese.