ImmoMulti — a direct buyer of income properties on the North Shore — regularly works with plex owners facing a mold problem. This issue is not just about health: it directly touches your legal duty to provide a dwelling in good condition, your tenants' remedies before the Tribunal administratif du logement (TAL), and your disclosure obligation at sale, on pain of a hidden-defect claim. According to the Government of Québec, mold proliferates as soon as humidity is high — which is why controlling infiltration and ventilation matters before the problem becomes costly or blocks a sale.
Must a plex landlord provide a mold-free dwelling?
Yes. The landlord has the obligation to provide a dwelling in good condition and fit for habitation. According to the City of Montréal, the landlord must keep all building components in good condition — roof, walls, windows, floors, balconies, stairs — and visible mold is prohibited under health and safety by-laws. To prevent mold, surfaces must remain dry.
The starting point of any mold problem in a plex is legal: the tenant is entitled to a dwelling in good condition, and it is the landlord's job to provide it and keep it that way. The City of Montréal states this clearly: the landlord is "responsible for maintaining all building components in good condition: roofing, walls, windows, floors, balconies, stairs, etc." Yet these are precisely the components — a leaking roof, a poorly insulated wall, a condensing window — behind most mold in a multi-unit building.
Municipal health and safety by-laws go further: any presence of visible mold is prohibited, as is water or humidity accumulation that degrades the structure or finishes. For a plex owner, this means a dwelling affected by mold is not merely "one to watch": it can be found non-compliant with minimum health standards.
Source: City of Montréal — "Tenant: you have the right to a dwelling in good condition" and City of Montréal — Housing health, maintenance and safety.
What causes mold in a plex?
According to the Government of Québec, mold proliferates in the presence of elevated humidity. Common causes in a plex are water infiltration (broken pipe, flooding, sewer backup) and insufficient ventilation that lets humidity from showers, baths and cooking accumulate. Indoor humidity should stay between 30% and 55% to prevent condensation.
The Government of Québec is unequivocal: mold proliferation occurs in the presence of an elevated humidity level. Understanding the moisture source is therefore key — for the occupants' health and for the value of your income property. Two broad families of causes recur in a plex.
Water infiltration
It is important to "identify and fix all causes of water accumulation or infiltration, such as broken pipes, flooding or sewer backup," the Government of Québec notes. In an older multi-unit building, an end-of-life roof, a foundation taking on water or aging plumbing continuously feed the humidity that nourishes mold.
Insufficient ventilation
"Insufficient ventilation inevitably causes excess humidity resulting from showers, baths and cooking activities," the Government of Québec observes. Proper ventilation is recommended, especially during humidity-producing activities. In a plex where units are occupied full time, everyday humidity accumulates if range hoods and bathroom fans are missing or deficient.
The simple rule to remember: keep surfaces dry
Indoor humidity should stay low enough to prevent condensation — usually between 30% and 55%. Watch for early signs: musty odours, condensation on windows, black spots on walls. Government of Québec — Finding and eliminating mould from your home.
Source: Government of Québec — Finding and eliminating mould from your home and Government of Québec — Health problems caused by mould.
What remedies does a tenant have at the TAL?
According to the Tribunal administratif du logement, a tenant may seek to cancel the lease or obtain an order requiring the landlord to perform work when inaction risks rendering the dwelling unfit for habitation. The tenant may also claim a rent reduction, damages and, where the landlord is negligent, punitive damages. The landlord may not re-rent a dwelling that remains unfit for habitation.
For a plex owner, the stake is not only the tenant's health: it is the range of remedies that opens up at the TAL if the problem is left unresolved. The Tribunal administratif du logement classifies the presence of mold or fungi among situations of unfitness (insalubrité) that can render a dwelling in poor habitability, or even unfit for habitation.
Concretely, a tenant facing mold may, according to the TAL:
- Cancel the lease or obtain a work order where failure to act risks rendering the dwelling unfit for habitation — or where it has already become so;
- Obtain a rent reduction for the period during which enjoyment of the dwelling is diminished;
- Claim damages for the harm suffered;
- Seek punitive damages where the dwelling became unfit for habitation through the landlord's negligence.
A concrete trap for the landlord
According to the TAL, the landlord may not re-rent the dwelling while it remains unfit for habitation. An unresolved mold problem can therefore freeze a unit of your plex — lost income on top of the cost of the work and any compensation.
Source: Tribunal administratif du logement — Unfitness (Insalubrité).
How does the City intervene on health standards?
According to the City of Montréal, the tenant must first notify the landlord. If the landlord does not act quickly, the tenant can report the problem to the City, which will assess whether an inspection is warranted. If the landlord does not make the corrections, the City can require work, impose fines and register a notice of deterioration in the land register.
The municipal route adds to the TAL remedy. The City of Montréal invites the tenant to notify the landlord in writing first and to keep a record of the exchange. For problems affecting walls, ceilings, windows or equipment in poor condition, it references a window to act on the order of 10 business days. If the landlord delays, the tenant can request a municipal inspection.
The consequences for a negligent plex owner are serious. Municipal teams can inspect, require corrective work and impose fines. Above all, in case of inaction, the City can register a notice of deterioration in the land register — a public registration that follows the building and cools buyers the day you want to sell.
"To prevent mold, surfaces must remain dry. Pay attention to musty odours, condensation on windows, water infiltration or black spots on walls."
— City of Montréal, Housing health, maintenance and safetySource: City of Montréal — Request an inspection of a dwelling.
Is mold a hidden defect when selling a plex?
Yes, potentially. According to Éducaloi, mold in the walls can constitute a hidden defect when it was concealed at the time of sale and could not be discovered during a normal pre-purchase inspection. The seller is responsible for the hidden defect even if unaware of its existence, and has a duty to inform the buyer of hidden defects they are aware of.
This is where the mold question meets the sale of your plex directly. Éducaloi explicitly cites "mold in the walls" among examples of hidden defects that, concealed at the time of sale and not detectable by a normal pre-purchase inspection, engage the seller's responsibility. The legal warranty against hidden defects applies automatically in principle, whether the seller is a professional or a private individual.
Two principles are especially consequential for a multi-unit seller:
- The seller is liable even in good faith. According to Éducaloi, the seller "is responsible for the hidden defect even if they were unaware of its existence" at the time of sale. Ignoring the problem does not protect you.
- The duty to disclose what you know. The seller must inform the buyer of the defects they know about so the buyer can evaluate repair costs. A known and concealed mold problem exposes you to a claim after the sale.
Expect to have to disclose
An "apparent" defect — visible on simple examination — is not covered by the legal warranty. But mold hidden in a wall or masked by a recent finish typically falls under hidden defects. An honest seller's declaration and a pre-purchase inspection protect both parties. Consult a notary or lawyer for your situation.
It is possible to sell without legal warranty, "at the buyer's own risk" — but this exclusion must appear in the promise to purchase and the deed of sale, and it does not cover the deliberate concealment of a known problem. To go deeper into hidden defects from the seller's perspective, see our article Hidden defects: protecting the seller of your plex.
Source: Éducaloi — The hidden defect in a building and Éducaloi — Real estate: buying without the legal warranty.
How much does mold decontamination cost in a plex?
The cost depends directly on the extent of the contamination and the cause to be corrected. The Government of Québec distinguishes small surfaces, often cleanable, from large or recurring surfaces that require professional evaluation, correction of the moisture source, and sometimes removal of materials. Decontaminating without correcting the cause solves nothing durably.
There is no single price: the decontamination cost of a plex varies with the affected area, the cause and the materials to be removed. The Government of Québec, in its technical information on evaluating and correcting mold problems, insists on a tiered logic: small surfaces on one hand, large or recurring contamination on the other.
| Situation | Typical approach | What drives the cost up |
|---|---|---|
| Small localized surface | Cleaning and drying, once the source is corrected | Porous materials to replace |
| Large or recurring surface | Professional evaluation, material removal, source correction | Extent, difficult access, rebuild after work |
| Structural cause (roof, foundation) | Envelope repair before any decontamination | Major roofing or drainage work |
The Government of Québec's central message is financially decisive for a plex owner: correcting the moisture source is essential. Cleaning mold without repairing the infiltration or ventilation merely postpones — and often worsens — the problem. That is why you should have the moisture source assessed by a professional before requesting any decontamination quote.
ImmoMulti: direct buyer of income properties on the North Shore
If your plex is dealing with a mold problem and you would rather not undertake decontamination work before selling, we can make you a direct, commission-free and confidential offer — on properties as-is. Get a proposal within 48 hours.
Before deciding between repair and sale, cost out both scenarios. Our multiplex yield calculation guide helps you evaluate the impact of a major correction on the overall value of your income property, while our pre-sale inspection of a plex article details the points to document before putting your multi-unit building on the market.
How to spot mold in a plex before it gets worse?
According to the Government of Québec, mold is a fungus whose spores are invisible to the naked eye and which grows in damp, poorly ventilated areas. The signs to watch for in a plex are stains, rippling or peeling paint, ceiling water marks, a persistent musty odour and condensation on windows. Detecting early means repairing at a lower cost.
For a plex owner, the worst enemy is not visible mold — it is the mold you cannot yet see. The Government of Québec makes the point: "The presence of stains, rippling or peeling, or other signs of water infiltration through walls or ceilings, may indicate a hidden problem." A dwelling may look spotless while a colony spreads behind drywall or under a floor. The longer the diagnosis waits, the higher the bill — and the legal risk.
Visual and olfactory signals you should never ignore
In a multi-unit building, vigilance must be systematic because occupants do not always report the first clues. Here are the signs every plex owner should check at each visit or between tenancies:
- Black, greenish or brownish stains on walls, ceilings, bathroom silicone joints or window surrounds;
- Paint that blisters, ripples or peels — a classic sign of moisture trapped behind the finish;
- Yellowish ceiling water marks, a clue of roof infiltration or a leak from the floor above;
- Musty or earthy odour that lingers even after airing out, often the first sign of hidden contamination;
- Heavy condensation on windows in the morning, revealing an excessive humidity level;
- Warped or crumbling materials at the base of walls, around bathtubs or in the basement.
Where to look first in a plex
Some areas concentrate the risk. The Government of Québec notes that mold "is often found in damp, poorly ventilated areas." In an income property, that means the basement (footings, slab, foundation walls), bathrooms without a fan or with a deficient one, the surround of older windows, poorly ventilated attics under a flat roof, and poorly insulated exterior walls where warm humid air condenses against the cold. A zone-by-zone checklist helps you miss nothing.
| Plex area | What triggers mold | Typical warning sign |
|---|---|---|
| Basement / foundation | Wall infiltration, capillary rise, deficient drain | Earthy smell, white efflorescence, damp lower wall |
| Bathroom | Absent or weak fan, frequent showers | Blackened joints, blistered ceiling paint |
| Kitchen | Hood not vented outside, steam cooking | Condensation, stains behind cabinets |
| Windows | Aging windows, thermal bridge, no airing | Persistent fogging, damp frame, mold at frame base |
| Attic / roof | Insufficient attic ventilation, infiltration | Water marks on the top-floor ceiling |
The winning reflex: inspect at every tenant turnover
The moment a unit is vacated is ideal for inspecting walls, ceilings, bathroom and basement without constraint. Document the condition with dated photos: they will serve both to prove maintenance and to prepare an eventual seller's declaration at sale time. Government of Québec — Finding and eliminating mould.
Source: Government of Québec — Finding and eliminating mould from your home.
What are the health effects of mold on occupants?
According to the Government of Québec, when mold grows significantly it releases particles into the air that, when inhaled, can cause cold-like symptoms, irritation of the mucous membranes (eyes, nose, throat) or a worsening of asthma attacks. Sensitive people should consult a health professional or call Info-Santé 811.
The health dimension is not incidental for a plex owner: it is what turns a simple maintenance defect into a threat to occupants' health, which weighs on both the TAL remedy and the "unfit for habitation" qualification. The Government of Québec is clear: "When it grows significantly, mold releases particles into the air that can cause health problems when inhaled."
The reported symptoms
Still according to the Government of Québec, exposed people "are likely to experience health problems such as cold-like symptoms, irritation of the mucous membranes (eyes, nose, throat) or a worsening of asthma attacks." Some people are more vulnerable: young children, seniors, and asthmatic or immunosuppressed individuals. In a multi-unit building, this can translate into repeated tenant complaints — a strong argument in an unfitness file.
Why health carries legal weight
A dwelling is deemed "unfit for habitation" when its condition is a serious threat to occupants' health or safety. Documented symptoms (a medical note, written complaints) therefore strengthen a tenant's position at the TAL — and weaken that of a landlord who did not act. Reacting quickly protects both occupants and your plex.
Source: Government of Québec — Health problems caused by mould.
Correcting mold in a plex, step by step
According to the Government of Québec, correcting a mold problem follows a precise sequence: identify and correct the moisture source, assess the extent of the contamination, clean small surfaces with an all-purpose cleaner (bleach is not necessary), then call a specialized company for surfaces larger than 1 m² or recurring ones. Decontaminating without correcting the cause solves nothing.
Too many plex owners start by scrubbing the visible stain — the reverse of what the Government of Québec recommends. The correct sequence protects both your budget and your liability. Here is the process, adapted to an income-property context.
Step 1 — Identify and correct the moisture source
This is the non-negotiable step. The Government of Québec insists: you must "identify and correct all causes of water accumulation or infiltration, such as broken pipes, flooding or sewer backups." In a plex, that can mean repairing a roof, sealing a foundation, replacing aging plumbing or installing an adequate fan. Without this correction, any cleaning is temporary.
Step 2 — Assess the extent of the contamination
The Government of Québec sets a clear reference threshold: small surface-mold areas (for example condensation on an exterior wall) can often be cleaned, while surfaces larger than 1 m², numerous, hard to clean or recurring justify a specialized company. This 1 m² distinction is the most useful benchmark for a plex owner deciding whether to treat it themselves or call a professional.
Step 3 — Clean small surfaces properly
For a small surface on a non-porous or easily cleanable material, the Government of Québec recommends wiping "the mold stains with a clean cloth and an all-purpose cleaning product," then drying the surface well. Importantly, to dispel a stubborn myth: "The use of bleach is not necessary." Porous, water-soaked materials (drywall, insulation, carpet) are replaced rather than cleaned.
Step 4 — Call a professional for larger cases
When contamination exceeds the threshold, the Government of Québec's technical information describes a complete process: find the cause, assess the contamination, plan and carry out decontamination, control the quality of the work, and communicate with the client. This is also the object of the BNQ 3009-600 standard, the first Québec standard governing mold decontamination in housing.
"If the affected surfaces are large (more than 1 m²), numerous or difficult to clean, or if the mold reappears after cleaning, it is recommended to call a specialized company."
— Government of Québec, Finding and eliminating mould from your homeSource: Government of Québec — Finding and eliminating mould, Government of Québec — Evaluating and correcting mold problems and Government of Québec — BNQ 3009-600 standard.
When does a plex become "unfit for habitation"?
According to the Tribunal administratif du logement, a dwelling is unfit for habitation when its condition constitutes a serious threat to the health or safety of the occupants or the public. A tenant may then abandon the dwelling, provided they notify the landlord of its condition before the abandonment or within the ten days that follow. Since February 2024, the Tribunal can also award punitive damages.
The notion of a "dwelling unfit for habitation" is the tipping point that should alert every plex owner. As long as a unit is merely "in poor condition," remedies stay measured. Once it becomes unfit, the consequences worsen sharply: the tenant can leave, the landlord cannot re-rent, and the TAL has heavier tools.
The definition used by the TAL
According to the Tribunal administratif du logement, a dwelling unfit for habitation is one whose "condition constitutes a serious threat to the health or safety of the occupants or the public." Significant mold contamination, especially with documented symptoms, can reach this threshold. The TAL classifies the presence of mold or fungi among unsanitary situations.
What the tenant can do
Facing a dwelling that has become unfit, the tenant may, according to the TAL, abandon the dwelling — but must then "notify the lessor of the dwelling's condition before abandoning it or within the ten days that follow." They may also seek termination of the lease or an order to perform work. A crucial point for the landlord: since February 21, 2024, the Tribunal can award punitive damages when a dwelling has become unfit for habitation.
The expedited procedure: ten business days
The TAL provides a fast track that changes the picture. Since February 10, 2020, "any application accompanied by documentary evidence (such as an inspection report or an evacuation order) demonstrating that a dwelling is unfit for habitation is scheduled for a hearing within ten business days of filing." For a plex owner, this means a well-built tenant file can move very quickly — all the more reason to act before it comes to that.
The combination to avoid at all costs
An unfit dwelling + documentary evidence + punitive damages possible since 2024: this is the costliest scenario for a landlord. A single ignored written mold notice can be its starting point. The best protection remains to correct the moisture source at the first report.
Source: Tribunal administratif du logement — Unsanitary conditions and Tribunal administratif du logement — Dwelling unfit for habitation: exceptional scheduling.
Repair or sell your plex: how to decide?
The choice between correcting the mold and selling the plex as-is depends on three variables: the extent and cause of the contamination, your ability to finance and coordinate the work, and the time available. Correcting restores habitability and removes the hidden-defect risk; selling as-is requires disclosing the known problem and, often, adjusting the price. Costing out both scenarios is the only way to decide objectively.
Once the diagnosis is made, every plex owner asks the same question: do I repair before selling, or sell as-is? There is no universal answer — only a costed answer specific to your building and situation. The starting point is to honestly compare both paths.
The "I fix it before selling" scenario
Correcting the moisture source, decontaminating and redoing finishes restores habitability, ends the TAL remedy risk and removes the hidden-defect qualification at sale. It is often the best choice when the cause is localized and the cost predictable (a bathroom fan and some drywall, say). When the cause is structural — roof, foundation, French drain — the bill and the timeline can become considerable, and nothing guarantees the buyer will pay a price reflecting your outlay.
The "I sell as-is" scenario
Selling without doing the work is perfectly legal provided you disclose the known problem. It is the route many owners take who have neither the time, the capital nor the desire to manage a decontamination project. The price then reflects the building's condition and the cost of the corrections to come, which the buyer assumes. This transparency is also what protects you from a claim after the sale.
| Criterion | Fix before selling | Sell as-is (with disclosure) |
|---|---|---|
| Immediate cost | High if structural cause; on you | None; assumed by the buyer via the price |
| Time before sale | Weeks to months (work + rebuild) | Fast; no project to wait on |
| Hidden-defect risk | Removed if the cause is well corrected | Removed by honest disclosure |
| Sale price | Potentially higher | Adjusted down to reflect the work |
| Management effort | Coordinating contractors, tenants | Minimal |
Cost it out before deciding
The golden rule: do not decide on instinct. Have the moisture source assessed by a professional, get a decontamination and rebuild quote, then compare the total cost (work + lost rent during the project + time) to the discount a buyer would demand for the building as-is. Often the gap is smaller than expected — especially when the cause is structural. Our multiplex yield calculation guide and our as-is plex sale guide detail this comparison.
A third path: the direct buyer
Between "fix everything" and "face the market with a known problem," there is an option: sell to a direct buyer of income properties who buys as-is, on the North Shore, without requiring prior decontamination. Get a costed offer within 48 hours and keep the comparison in hand.
Source: Éducaloi — Real estate: buying without the legal warranty.
Documenting and disclosing: protecting the plex seller
The seller of a plex must inform the buyer of hidden defects they know about, including a mold problem. The best protection is to document every intervention (dated photos, invoices, reports), to fill out the seller's declaration honestly, and to favour a pre-purchase inspection. Concealing a known problem exposes you to a claim, even in a sale concluded "without legal warranty."
Documentation is the most underrated tool of the plex seller. A solid file does two things at once: it proves you maintained the building and corrected problems, and it materializes the disclosure that shields you from a hidden-defect claim.
What to keep
- Dated before/after photos of each intervention on moisture or mold;
- Contractor invoices (roofing, plumbing, ventilation, decontamination) specifying the nature of the work;
- Inspection or expert reports on the moisture source;
- Written exchanges with tenants: notices received, replies, intervention dates;
- Decontamination certificate or report if you used a specialized company (ideally compliant with the BNQ 3009-600 standard).
The seller's declaration
The seller's declaration is the document where you record what you know about the building's condition. Honestly noting a mold history, its cause and its correction is not an admission of weakness: it is your shield. According to Éducaloi, the seller must inform the buyer of the defects they know about so the buyer can evaluate the costs. A transparent declaration makes it much harder for a buyer to later claim they were misled.
Selling "without legal warranty": the limits
It is possible to sell at the buyer's own risk, without the legal warranty. But this clause has a major limit: according to Éducaloi, it does not cover the deliberate concealment of a known problem. In other words, the warranty exclusion does not protect you if you knew and said nothing. Transparency therefore remains essential, even in a sale without warranty.
The mistake that costs the most
Repainting or masking a mold trace just before showings, without disclosing the history, is exactly the behaviour that opens the door to a hidden-defect — or even fraud (dol) — claim. Active concealment is far riskier than honest disclosure. Consult a notary or lawyer for your specific situation.
Source: Éducaloi — The hidden defect in a building.
Common mistakes plex owners make with mold
The costliest mistakes are: cleaning mold without correcting the moisture source, ignoring a tenant's first written notice, masking the problem before a sale without disclosing it, underestimating ventilation, and using bleach believing it solves the problem. Each exposes the owner to recurrence, a TAL remedy or a hidden-defect claim.
After helping many plex owners on the North Shore, the same traps come up again and again. Knowing them is already avoiding them.
Mistake 1 — Treating the symptom, not the cause
This is the number-one mistake. Cleaning the stain without correcting the infiltration or ventilation guarantees a recurrence. The Government of Québec is categorical: you must "identify and correct all causes of water accumulation or infiltration." Decontamination without source correction is money thrown away.
Mistake 2 — Letting a written notice sit
Ignoring or being slow to respond to a tenant's written notice is the surest way to turn a minor incident into a TAL file. The City of Montréal references an action window on the order of 10 business days for problems affecting walls, ceilings or windows. Reacting quickly and in writing is your first protection.
Mistake 3 — Betting on bleach
Many believe bleach "kills" mold and fixes everything. The Government of Québec specifies that "the use of bleach is not necessary": an all-purpose cleaner is enough on a small non-porous surface, and above all, no product replaces correcting the source or removing water-soaked porous materials.
Mistake 4 — Neglecting ventilation
A bathroom fan that is absent, disconnected or vents into the attic rather than outside is a chronic moisture cause. The Government of Québec recalls that "insufficient ventilation inevitably causes excess humidity." Checking and correcting ventilation costs little and prevents much.
Mistake 5 — Camouflaging before selling
Repainting over it without disclosing is the false good idea par excellence. It does not make the legal risk disappear — it worsens it, opening the way to a hidden-defect or fraud claim. Honest disclosure is always the safest strategy.
Cheat sheet: the right reflex in five points
- Correct the moisture source before cleaning.
- Respond in writing to any tenant notice, without delay.
- Call a professional once the surface exceeds 1 m² or recurs.
- Document every intervention (photos, invoices, reports).
- Honestly disclose any known history at sale.
Source: Government of Québec — Finding and eliminating mould and City of Montréal — Dwelling in good condition.
Preventing mold in a plex on the North Shore
Prevention rests on three pillars: keeping indoor humidity between 30% and 55%, ensuring effective ventilation of bathrooms and kitchens, and correcting any infiltration without delay. On the North Shore, freeze-thaw cycles and heavy rains put roofs, foundations and drains under particular strain — hence the importance of seasonal preventive maintenance of the building envelope.
Prevention always costs less than correction. For a plex owner on the North Shore, where the climate tests the building envelope, a few habits sharply reduce the risk of mold — and therefore of remedies and sale-price discounts.
Control the humidity level
The Government of Québec recommends keeping the dwelling's humidity low enough to avoid condensation, generally between 30% and 55%. An inexpensive hygrometer installed in sensitive areas (basement, bathroom) lets you monitor this. In winter, condensation on windows is the visible signal of an excessive level.
Ventilate effectively
Bathroom fans and kitchen hoods must exhaust humid air to the outside, not into the attic. In a plex, check that each unit has functional ventilation and remind occupants to use it during showers and cooking — the two main indoor moisture sources according to the Government of Québec.
Maintain the building envelope
On the North Shore, seasonal preventive maintenance is decisive: inspect the roof in spring and fall, clean the gutters, check drainage around the foundation, and pay particular attention after every heavy-rain or rapid-melt episode. Correcting an emerging infiltration costs a fraction of a major decontamination.
A simple maintenance calendar
- Spring: inspect roof and gutters, check post-thaw drainage.
- Summer: check ventilation, replace weak fans.
- Fall: clean gutters, seal cracks before winter.
- Winter: watch condensation on windows and the humidity level.
This preventive discipline protects both your tenants and the resale value of your multi-unit building. A property with no mold history sells faster, without a discount and without fear of a hidden-defect claim.
Source: Government of Québec — Finding and eliminating mould.
Informational content only. Does not constitute legal or tax advice. Health, housing and hidden-defect rules are applied case by case. Consult a notary, lawyer or qualified professional for advice specific to your property and situation.
