Hidden defect in your property: what to do when you discover problems after the purchase, and what are the deadlines to claim?

The move is done, the first rain arrives — and with it the water infiltration that the fresh paint was hiding. Or the chronic clogging, the leak inside the wall, the crack that keeps reopening. Every buyer asks the same question at that moment: “is this my problem now?”. The law's answer is: it depends on three things — the nature of the defect, who sold the property and, above all, how quickly you act.

A hidden defect is a flaw that existed before the sale, could not be seen, and makes the property unfit for its intended use or lowers its value — to the point that the buyer, had they known, would not have bought it, or would have paid less (art. 441 of the Brazilian Civil Code). In this article, we cover what counts as a hidden defect, the buyer's rights, the deadlines (which are short and unforgiving), the differences between buying from a private seller and from a developer, and the step-by-step response.

What is (and what is not) a hidden defect?

The test has three filters: did the defect predate the purchase? Was it undetectable in a diligent inspection? Does it compromise the use or the value of the property? Pass all three, and it is a hidden defect: water infiltration masked by fresh paint, condemned electrical wiring behind the finishes, a concealed structural problem. It is not: visible natural wear, a defect that arose after the sale, or anything that was in plain sight during the visit. The most contested boundary is “detectability” — and that is exactly where the expert report decides cases.

What are the buyer's rights — and the deadlines to exercise them?

Once the defect is discovered, the Civil Code offers two actions to choose from (art. 442): the rescission action (ação redibitória) (undo the deal, returning the property and getting the price back — and, if the seller knew about the defect, damages too, art. 443) or the price-reduction action (ação estimatória) (keep the property and demand a proportional reduction of the price). The clock is harsh: the strict deadline for real estate is 1 year, counted from delivery — and, if the defect can only be discovered later, it runs from the moment you learn of it (art. 445, main text and § 1º). This kind of deadline is not paused by friendly negotiation: while you trade messages with the seller, time keeps running.

I bought from a developer: what changes?

The arsenal changes. Because it is a consumer relationship, you also get: a deadline of 90 days from discovery to claim for hidden defects (art. 26, II and § 3º, of the CDC) — interrupted by a documented complaint to the supplier (art. 26, § 2º) —, the developer's strict liability, and the shifting of the burden of proof in the consumer's favor. And, for defects compromising soundness and safety (structure, foundations, severe water infiltration), art. 618 of the Civil Code imposes a statutory warranty of 5 years from delivery of the works. The case law of the STJ (Brazil's Superior Court of Justice) also allows, for damages claims, longer limitation periods than the warranty deadlines — so “I missed the deadline” always deserves a second technical look before it turns into giving up.

The step-by-step response: document, notify, act

1. Freeze the evidence: dated photos and videos, before any repair;
2. Expert report (engineer or surveyor): origin, pre-existence and cost of repair — it is the heart of the case;
3. Formal extrajudicial notice to the seller/developer, describing the defect and the demand (repair, price reduction or undoing the deal) — under the CDC, it stops the deadline from expiring;
4. Negotiation with a set deadline — and, if there is no solution, a lawsuit within the legal time limits;
5. Fix emergencies to keep the damage from getting worse, but document first and keep the invoices: documented expenses are added to the compensation.

A concrete example: Marcos and Paula's house in Lapa

Forty days after moving in, the rains revealed widespread water infiltration in the concrete slab — hidden under fresh paint and plaster, applied weeks before the sale. The expert report identified a long-standing waterproofing problem: a repair of R$ 48,000 on a property bought for R$ 720,000. A formal notice went out with the report in hand, plus evidence of the recent paint job (the listing photos!) suggesting the seller knew about the defect. Facing the risk of also being liable for damages (art. 443 of the Civil Code), the seller settled: a R$ 55,000 price reduction covering the repair and the disruption. Total time: 70 days — because every step was taken within the deadline and backed by evidence.

The most common (and costly) mistakes

1. Renovating before documenting. The repair erases the proof of the defect and of its pre-existence. Risk: being right without being able to prove it.
2. Negotiating informally until the deadline expires. Risk: 1 year (Civil Code) and 90 days (CDC) go by fast; a WhatsApp chat does not stop the clock — a formal notice does (under the CDC).
3. Confusing a hidden defect with buyer's remorse. A defect visible during the visit, or one that arose later, creates no right. Risk: litigating a lost case and paying the other side's costs.
4. Skipping the expert report “to save money”. Risk: without technical proof of the origin and pre-existence, the claim becomes word against word.

Actionable checklist when you discover a defect

• Dated photos/videos of the problem, without touching anything;
• Sales listing, photos from the time and inspection report filed away;
• Expert report: origin, pre-existence, severity and repair estimate;
• Formal extrajudicial notice within the deadline (90 days/CDC; 1 year/Civil Code);
• Emergencies repaired only after documenting — invoices kept;
• No settlement within the set timeframe: file the lawsuit before the deadline expires.

Frequently asked questions

What counts as a hidden defect in a property?

It is a defect that existed before the purchase, was undetectable in a diligent inspection, and makes the property unfit for use or reduces its value (art. 441 of the Brazilian Civil Code): masked water infiltration, concealed structural problems, condemned wiring or plumbing hidden behind the finishes. Visible wear and tear, defects you could see during the visit and problems that arose after the sale do not qualify.

What is the deadline to claim for a hidden defect in a property?

Between private parties: a strict deadline of 1 year (art. 445 of the Civil Code), counted from delivery — or from discovery, when the defect only reveals itself later. From a developer: 90 days from discovery (art. 26 of the CDC), interrupted by a documented formal complaint; and a 5-year warranty for defects affecting soundness and safety (art. 618 of the Civil Code). The clock keeps running even during informal negotiations.

I found the defect: can I undo the purchase or only ask for a discount?

The choice is yours (art. 442 of the Civil Code): the rescission action (ação redibitória) undoes the deal with a refund of the price — and, if the seller knew about the defect, adds damages (art. 443) —, while the price-reduction action (ação estimatória) keeps the purchase with a proportional price reduction. In practice, repairable defects tend toward a reduction or repair; defects that compromise the use of the property justify undoing the deal.

The seller says they did not know about the defect: are they still liable?

Yes. Liability for a hidden defect does not depend on the seller's knowledge (art. 443 of the Civil Code): if they were unaware of it, they refund the amount received plus expenses; if they knew, they are also liable for damages. Bad faith (such as fresh paint covering water infiltration) increases the compensation — and is usually exposed by the expert report and the listing photos.

When should I see a lawyer about a property defect in São Paulo?

Immediately after the discovery — before renovating and before negotiating on your own. The limitation deadlines are short (90 days under the CDC; 1 year under the Civil Code) and the evidence strategy (expert report, formal notice that stops the deadline) is set in the first few days. Most well-documented cases end in a price-reduction settlement without ever needing a court ruling.

With hidden defects, whoever documents first decides the outcome

The buyer's right exists and is strong — but it lives on technical evidence and dies by expired deadlines. Photograph before repairing, get the expert opinion before accusing, and send the formal notice before time runs out: that sequence turns the first-rain infiltration into a price reduction, not a permanent loss.

At Falchet e Marques Sociedade de Advogados, a law firm in São Paulo (Av. Paulista), we handle hidden defect and construction defect cases: an evidence strategy built on the expert report, notices that preserve your deadlines, and the right action — rescission, price reduction or damages — against sellers and developers.

Talk to our team on WhatsApp: +55 11 95901-1854 — describe the defect you found and how long ago you received the property, and find out which deadlines and rights still run in your favor.