A crack appears above a window, or steps down the corner of the house, and the worst-case scenario arrives with it. Most of the time it should not. Walls move, renders shrink, and the Costa del Sol's heat and occasional heavy rain open cracks that are entirely cosmetic. Some, though, are worth attention. Here is how we read them on a first visit — a calm triage, not a diagnosis by article, because a crack has to be seen to be judged.
Hairline cracks in render and plaster
Fine, shallow cracks in the surface render or internal plaster — the width of a hair, following no particular pattern — are the most common and the least worrying. They are the surface reacting to heat, cold and time, not the structure moving. They are cosmetic: cut out, fill, and repaint with a breathable finish and they are gone. If they keep coming back in the same place that is worth mentioning, but on their own they are just a wall being a wall on a hot coast.
Cracks at window and door corners
Cracks running diagonally from the corners of windows and doors, or along the line of a lintel, are common in Spanish construction. Openings concentrate stress, and a little movement shows up at the weakest point. Usually these are repairable — rake out, reinforce, re-render — and stable once done. We look at whether the lintel itself is sound and whether the crack is old and settled or fresh and moving, which changes the fix.
Stepped and diagonal cracks in block or stone
Cracks that step down through the mortar joints of block or stone, especially wider ones, deserve a proper look. They can point to movement in the wall or the ground beneath it rather than just the surface. Often they are historic and long since stable; sometimes they are not. This is the category where we would rather see it in person and, if there is any doubt, bring in an aparejador (technical architect) or structural engineer before deciding anything.
Cracks that widen over months
The single most useful thing you can do with a crack that worries you is to date it. Mark each end with a pencil line and the date, and photograph it. A crack that has not moved in six months is telling you it is stable; one that is visibly wider than your mark is telling you the opposite. That simple record is worth more than any amount of speculation, and it is exactly what a professional will ask for.
Cracks after heavy rain or on hillside plots
On the steep plots of the villages and the campo, water and ground movement go together. A crack that appears or worsens after heavy rain, on a wall that backs onto a slope, often has drainage behind it — water pressure against or under the wall. Here the fix is frequently outside the house, not in it: drainage, gutters and downpipes first, then the wall. It is a close cousin of the problems in our guide to render and why coastal walls fail.
What we do at a free visit
When you send us a photo or we come out, we are working out which of the above you have: whether it is surface or structural, old or moving, dry or fed by water. For the cosmetic majority we cut out, repair and repaint, and it is done. For the small number that are structural, we are honest that it needs an aparejador or engineer, and we will not paper over something that needs proper attention — filling a moving crack just hides it until next year. Either way you get a straight answer and, if there is work to do, a written quote. We do this on houses from Torrox to the inland villages every week.
Worried about a crack? See our plastering and repair work, or explore a full reform if the house needs more, and send us a dated photo for a free, honest assessment.
