Renovation & construction
Damp in a flat before buying: source, signs and who pays
Damp reaches a flat with rain, from the ground, through pipes or from the air. How to tell the source at a viewing, when to call a technician and why damp visible before the deal is hard to claim.
Signs of damp in a flat are looked for not by the size of the stain but by the source: the estimate and who pays for the repair depend on it. Spain's Código Técnico de la Edificación (CTE, the Technical Building Code) names four sources of water in a building: precipitation, surface run-off, the ground and condensation (art. 13 CTE, HS 1). If the cause is in the facade or the roof, the repair is decided by the comunidad (owners' association), not by the flat's new owner.
Where damp in a flat comes from
Damp in a flat is water that has got inside the walls and rooms and does not leave. Each source has its own signature, and identifying it matters more than judging the stain.
| Source | What it looks like | Where to look | Whose elements these usually are |
|---|---|---|---|
| Precipitation through roof, terrace, facade | Rings with a sharp edge on the ceiling, damp under windows after wind-driven rain | Top floor, under a neighbour's terrace, external walls | Common: roof, facade |
| Ground, rising damp | A band of damp at floor level, flaking plaster, white salts | Lower levels, semi-basements, houses on a slope | Common: foundations, walls |
| Pipes and risers | A stain near the bathroom, the kitchen, the riser | Walls with pipes, the ceiling under a neighbour's bathroom | Inside the flat, or a common riser |
| Condensation | Black dots of mould in corners, behind wardrobes, on window reveals | External walls, a bathroom with no extractor, windows onto a courtyard | The flat: ventilation, windows |
The column on who owns the elements is indicative: where the line between common and private runs in a particular building is set by the statutes and by the abogado (lawyer).
What can be seen at a viewing without instruments
A flat is often shown on a sunny day, with windows open and freshly painted, so details are looked at rather than the general impression.
- Stains, rings and blistered paint in the corners of walls and ceiling.
- A white bloom of salts on the plaster.
- Loose tiles and dark grout in the bathroom.
- Swollen laminate or parquet by an external wall.
- Mould behind furniture, behind the bedhead, behind curtains.
- Streaks on window reveals.
- A smell of damp that does not go away with the windows open.
- A dehumidifier in the room, or a single freshly painted wall in an old refurbishment.
It is worth pulling furniture away from the external wall. If the seller objects, that is information too. The remaining points of the inspection are collected in the flat viewing checklist.
How to check a flat for damp before the arras
The order of checking runs from what is costlier to fix to what is cheaper.
- Go through the control points: corners of external walls and the area under windows, the ceiling under a neighbour's terrace or bathroom, the wall with the riser, skirting boards and the lower half-metre of walls on lower floors, the storage room and trastero, windows onto an inner courtyard.
- Ask the seller in writing: whether there have been leaks, who fixed them and how, whether the insurer was contacted, why this particular wall is painted.
- Ask the administrator for the minutes of owners' meetings: roof or facade repairs, complaints about leaks, derramas (special levies) approved for waterproofing.
- If the source is not obvious, damp at floor level in an old building or marks under the roof, bring in an arquitecto (architect) or aparejador (building technician) with a moisture meter and, if needed, a thermal camera.
- Get an estimate of the cost of the works and make it part of the price offer.
If the flat is on a low level or on the top floor, the floor deserves separate attention, with detail in the article on the floor and the lift.
Who pays if the facade or the roof leaks
If the source is in common elements, the repair must be done by the comunidad: under Catalan law the comunidad keeps common elements in a state that meets the requirements of soundness, habitability and watertightness, and the owners bear the necessary works (art. 553-44 of the Código Civil de Cataluña (CCCat, the Civil Code of Catalonia)). All owners pay in proportion to their share (art. 553-45).
For a buyer this is two pieces of news. The good one: a leak through the roof does not fall on the buyer alone. The bad one: the timing is decided by the meeting, until the repair the damp stays in the flat, and the future derrama will enter the buyer's costs. That is why, before the arras (reservation deposit contract), it is established whether the problem was discussed and whether the repair is approved.
What if damp is discovered after the purchase
Catalan law protects a buyer against a lack of conformity of the goods with the contract, but with a weighty reservation. The seller is not liable for a lack of conformity that the buyer knew of or could not reasonably have been unaware of when the contract was made, except in cases of deliberate concealment, gross negligence or an express guarantee (art. 621-26 CCCat).
So damp visible at the viewing turns from an argument against the seller into an argument for bargaining before signing. If the problem does show up after the purchase, the seller is notified without undue delay (art. 621-29), and the time limits for claims under Catalan law run from the moment the buyer learned of the lack of conformity (art. 621-44). Whether these rules apply to a specific deal and flat is assessed by the abogado. How a technical report helps to find hidden defects is covered in the article on hidden defects.
When buying a flat with damp does not work
It does not work if the cause could not be established and the seller gives no time to check: you cannot bargain blind. Such a flat also does not suit a buyer who needs to move in at once: repairing the waterproofing of a facade or roof depends on the meeting and can take a season.
If the cause is local and clear, for example an old pipe or a bathroom with no extractor, the damp becomes a budget line and a negotiating argument. DNPI does the price assessment taking the works into account as part of a property value analysis.
Questions and answers
Can you buy a flat with damp?
You can, if the cause is clear and there is a realistic estimate of the works. If the source is unknown or tied to common elements of the building, the decision is postponed until a specialist's opinion.
How do you tell condensation from a leak?
Condensation appears on cold surfaces, in the corners of external walls and behind furniture, and gets worse in winter with the windows closed. A leak leaves rings with a sharp edge, often on the ceiling or by pipes, and does not depend on ventilation.
Who pays for the repair if the common roof leaks?
Under art. 553-44 of the Código Civil de Cataluña the comunidad maintains common elements, and all owners pay according to their share. Before buying it is worth finding out whether the repair has already been approved and what derrama is expected.
Can damp that was visible at the viewing be claimed from the seller later?
As a rule it is difficult: under art. 621-26 CCCat the seller is not liable for a lack of conformity that the buyer knew of or could not have failed to notice, except for concealment, gross negligence or a guarantee. That is why visible damp is priced in before the deal.
Is it worth viewing a flat after rain?
Yes, if there is a chance. Leaks through the roof, terrace and facade show better after heavy rain, and the smell of damp is stronger on a cold, overcast day.
