Which cracks and damp should you look for when viewing a flat?

Why the viewing matters more than it seems

The Spanish Civil Code gives a buyer six months from handover to claim for hidden defects, and the seller is not liable for defects that were «manifest or in plain view» (articles 1484 and 1490). In practice, a crack or a damp stain you could see at the viewing will be hard to claim for later, so look for it, write it down and ask about it before you sign anything, including the arras (the deposit contract that usually comes before the deed in Spain).

If the flat is new or recent, the Spanish Building Act adds its own periods from the handover of the works: ten years for damage to foundations, beams, floor slabs, load-bearing walls and other structural elements; three years for defects affecting habitability; and one year for finishes (article 17). In a resale flat built decades ago those periods have long expired, and everything depends on what you find out before you buy.

This guide will not teach you to diagnose a building. It shows you how to look methodically, how to document what you see and how to recognise when a sign deserves a visit from an architect or a building surveyor (arquitecto técnico) before you make an offer.

Where to look: from the street inwards

Start outside. Look at the whole façade, not just the flat's windows: cracks running diagonally from the corners of windows, missing render, safety netting or scaffolding, balconies with rust stains underneath and flaking cornices. Then the entrance and the stairwell: stained ceilings, uneven steps, cracks that repeat in the same spot on several floors.

Inside the flat, follow the same order in every room: ceiling, the joint between ceiling and walls, the corners of doors and windows, the bottom of the walls next to the skirting, and the floor. Open built-in wardrobes and, if you are allowed, look behind large furniture: that is where damp shows first and where people repaint least.

Pay special attention to bathrooms and the kitchen (grout, the ceiling under the flat above, skirting), walls facing the street or an inner courtyard, top-floor ceilings under the roof, and ground floors and basements. If the building has a car park or storage rooms, go down: car-park ceilings often show the condition of concrete you cannot see from the flats.

Cracks: what to note without drawing conclusions

Not all cracks are alike, but you cannot tell their cause by looking. What helps is describing them well: where they are, how long they are, which way they run (horizontal, vertical or diagonal), whether they go through the paint only or the plaster too, whether they repeat on the ceiling below or on the façade, and whether they have been filled before.

The Spanish structural safety code treats deformations (deflection, settlement, leaning) as something checked with calculations and professional judgement, not by eye. Some signs are therefore worth noting rather than interpreting: doors that stick or will not close, noticeably sloping floors, sagging ceilings, cracks that widen towards one end or appear on facing walls at the same time.

A fine, isolated hairline crack in the paint of a partition wall is usually minor, and a dramatic-looking crack may have a simple explanation. The goal is not to guess the cause but to leave with a description that lets a professional decide whether it needs a closer look.

Damp: four possible sources

The Spanish Building Code names four sources of water a building must deal with: rain, surface run-off, the ground and condensation (Basic Document HS, requirement HS 1). Each leaves a different trace and they often mix, so at a viewing it is enough to know there are several possibilities and to note where the stain is.

Signs worth looking for: yellowish or ringed stains on ceilings, black mould spots in corners and behind curtains, blistered or flaking paint, efflorescence (white powder or crust of salts) at the bottom of walls, a musty smell that does not go away when you air the room, swollen skirting boards and darkened wooden floors or frames.

A freshly painted wall in an otherwise unrenovated flat is not a bad sign in itself, but it is a good question. So is a dehumidifier running or windows wide open in midwinter. Ask casually; the answer, and how readily it comes, is information too.

Quick checklist for the viewing

Façade and entrance: diagonal cracks next to openings, fallen render, rust under balconies, safety netting, stains on stairwell ceilings.

Ceilings in the flat: ringed stains, long parallel cracks, sagging areas, blistered paint; on the top floor, stains next to the façade or under the roof.

Walls: cracks at the corners of doors and windows, damp just above the floor, white salts, mould in cold corners and behind wardrobes.

Doors, windows and floors: doors that stick, windows that do not close properly, condensation on the glass, tiles that are lifting or sound hollow, floors that slope.

Shared areas below ground: car-park or storage ceilings with flaking concrete, exposed or rusty steel reinforcement, water seeping through walls.

What to photograph and how

Ask permission to take photos and always take two of each sign: a wide one showing which room and which wall, and a close-up. Put something next to it for scale (a coin, a pen or a tape measure) and shoot with light from the side, which shows the relief of cracks better.

Also record a short video of the whole tour, room by room, saying out loud where you are. Save the photos with the date and the room name. If you visit again, repeat the same shots from the same spot: comparing two dates tells you more than a single picture.

This record helps in three ways: a professional can decide whether a sign needs a visit, you can negotiate with facts rather than impressions, and you can show what was in plain view on the day you saw the flat if something that was not there turns up later.

What to ask the seller and the owners' association

Ask the seller: the year of construction and of the last renovation, whether there have been leaks or water-damage claims and what was repaired, whether building works or special levies (derramas) have been approved, and why a particular wall was repainted recently if that is the case. For recent buildings, ask for the date the works were handed over: the Building Act periods run from that date.

Ask the owners' association (comunidad de propietarios), through the seller or the property manager: the minutes of recent meetings (damp in the façade, roofs or car park and the agreed repairs show up there) and the result of the last building inspection (ITE or IEE in Spanish). In the Valencia region, for example, it is compulsory for buildings over 50 years old, valid for ten years from registration, and its summary can be looked up in a public register.

A favourable inspection means no defects were recorded on the date it was carried out, not that the building has none. One with defects does not mean the flat is in bad shape, but it does mean there are repairs with deadlines that the owners will have to pay for, and that affects your decision and your offer.

What HOUSINGFAX tells you before the viewing

Arriving at a viewing knowing what to look for changes the conversation. The HOUSINGFAX report brings together 22 checks on official Spanish sources in one document, each with a traffic-light rating (✓ no alert, ⚠ worth noting, ○ no data), its source and its date. Check 01 summarises the recorded condition of the building when the inspection is in an integrated regional register (currently the Valencia region, the Basque Country and Madrid), with the defects and their deadlines.

Other checks tell you what to look at more carefully: 02 lists the usual risks for buildings of that construction year, 03 gives the probability of aluminosis as a level in words, with its reasons, 10 whether the plot lies in a mapped flood zone and 13 whether satellites record ground movement. Everything ends in a list of points to check, written to take with you to the viewing.

You can start with «Check your home for free»: the free report shows the cover and the traffic-light rating of every check. The Essential report costs €11 and the Complete report, with the building's condition, €19, as a one-off payment with no sign-up. Look at the sample report first to see what you will get.

When to call a professional before making an offer

Some signs justify a professional visit before you make an offer or sign the arras: cracks that go through the wall or show both inside and outside, cracks repeating on several floors, doors and windows that will not close, noticeably sloping floors, sagging ceilings, concrete falling off, exposed or rusty reinforcement steel, and extensive damp or damp of unknown origin.

Find an architect or a building surveyor (arquitecto técnico), show them your photos and your list, and ask whether an inspection is needed and what it would include. If there is pressure to sign quickly, ask for the visit to happen before, not after: once you have signed, your room to negotiate shrinks. Neither this guide nor the HOUSINGFAX report replaces an on-site technical inspection of the building; they help you know what to ask and where to look.