Damp coming from the upstairs neighbour: what to do

How do you know the damp comes from the upstairs neighbour?

In a fração (unit) on a middle floor, a ceiling patch has few possible sources: the neighbour's home above, a shared pipe running between floors, or condensation. If you live on the top floor, the roof joins the list — see the guide on mould on the ceiling.

The signs pointing upstairs are fairly characteristic:

• A ring-shaped patch (yellowish or brownish edge) under the neighbour's bathroom, kitchen or washing machine area.
• It grows irregularly, with no link to rain — sometimes it darkens after someone showers upstairs.
• Blistered paint, drops or crumbling plaster, rather than black spots spread across the corners.
• It appears suddenly, after building work or the replacement of an appliance upstairs.

The free diagnosis cross-checks these signs and gives a probability for each hypothesis, with a leak alert when your answers justify it. For the full method, see the guide on water ingress.

The meter test: how to confirm a leak

The simplest test uses the neighbour's water meter, not yours. Ask them to turn off every tap, not use the toilet cistern or appliances, and note the meter reading. After 30 to 60 minutes, read it again. If the meter has moved with everything off, there is a leak in that unit's supply.

If the meter stayed still, a leak in the pressurised pipework is unlikely, but waste-water or seal leaks are not ruled out: worn shower-tray joints, bath silicone, the trap or the toilet connection. These only let water through when they are used.

If none of this gives a clear answer, professional leak detection (thermal imaging, tracer gas, camera) costs from a few hundred euros. It can be worth it before breaking open ceilings or floors at random.

Talk to the neighbour first

Most of these cases are solved with a conversation. The neighbour often doesn't know they have a leak. Bring photos of the patch, explain when it appeared and suggest doing the meter test together.

If the person upstairs is a tenant, repairing that unit's plumbing is, as a rule, their landlord's job. Ask for the owner's contact or ask the building management. And if you are a tenant, tell your own senhorio (landlord) too: repairing your ceiling is, in principle, their matter — see who pays in a rented home.

If relations between neighbours are already tense, you can ask the building management to act as a go-between or to be present at the first conversation. It is not compulsory, but a third person helps keep the discussion on the facts: the patch, the dates and the test.

Notify in writing: what to include

If the conversation doesn't solve it within a few days, or the neighbour doesn't reply, put it in writing. A registered letter with proof of receipt or an email with a read receipt records that the neighbour was informed — which may matter if the damage grows.

• The date the patch appeared and where it is (which room, and under which of the neighbour's rooms).
• Dated photos and, if you have them, humidity readings.
• What you are asking for: a check of the plumbing or seals and a repair within a reasonable time, for example 15 days.
• That you intend to report the claim to your insurer, and a request for the neighbour's policy details.

The template letters the site generates are designed for landlords and building management — they are on the tenants and condominium pages and in the diagnosis result. They are a good base for structuring a letter to the neighbour. They are templates, not legal advice.

Insurance: "danos por água" and who claims

Home multi-risk policies usually include water damage cover (danos por água), designed for sudden events such as a burst pipe or an overflowing machine. Slow leaks and lack of maintenance are often excluded. Check the specific conditions (condições particulares) of your policy.

As a rule, three policies may be involved: yours (damage to your ceiling and contents), the neighbour's (damage to their home and, if they have it, third-party liability for damage caused to others) and the condomínio's, if the source is a shared pipe. Often the quickest route is to claim on your own insurer, which then deals with the neighbour's.

When the pipe is shared: the building management

Water and waste stacks serving several units are, as a rule, common parts of the building (Código Civil, art. 1421), and their upkeep is paid by the owners in proportion to their permilagem (share of the building, in thousandths) under art. 1424. If the neighbour's meter test is negative and the patch is next to a stack, that may be the source.

In that case, the notice goes to the condomínio's management, with a copy to the neighbour. The branch pipe inside each unit is usually the unit owner's responsibility; the exact boundary may depend on the building's rules. More in the guide on common parts.

No agreement: mediation, Julgados de Paz and realistic timelines

When the neighbour refuses or ignores you, there are alternatives before the ordinary courts. The Julgados de Paz (justice of the peace courts) handle disputes between neighbours and between unit owners, with simple procedures, low costs and a mediation stage. Check with DECO or with your local julgado whether your case falls within their remit.

Once the leak is fixed, a plaster ceiling can take weeks to dry. Painting too early brings the stains back. This article is general information, not legal advice: if in doubt, talk to a lawyer or to DECO.