Updated on 26 June 2026 · by Pepe, painter in Elche
Almost every house has the odd crack, and most of them are nothing serious. I'm Pepe, a painter in Elche, and I'll help you tell the purely cosmetic ones (filled and painted over) from the ones a surveyor should look at before you cover anything up.
How to tell them apart
As a rough guide (it doesn't replace a surveyor if you're in any doubt):
| Type of crack | Appearance | What it usually is |
|---|---|---|
| Fine / hairline | Like a hair, surface-level, in a layer of paint or plaster | Cosmetic: filled and painted |
| Joint or junction | Where plasterboard meets, at the ceiling-wall line or around doors | Cosmetic/movement: sealed and painted |
| Wide, stepped or diagonal | Thick, follows the brick joints, opens and closes | Possibly structural: have a surveyor look |
Signs it's worth having it checked
No need to panic, but don't just cover it up if you see this:
- Wide cracks (more than a few millimetres) or ones that grow over time.
- A stepped shape following the bricks, or running diagonally from the corners of doors/windows.
- They appear at once on several walls, or run right through from side to side.
- Doors or windows that have started to catch or won't close properly.
How the cosmetic ones are repaired before painting
Fine and joint cracks, which are the vast majority, are sorted properly and disappear once painted: I open the crack up a little, clean it out, fill it (with flexible filler on joints that move), sand it and prime it before the colour goes on. That way it doesn't show through again a few weeks later, which is what happens when you just slap paint over the top.
When I'll tell you to stop
If I look at it and reckon the crack might be structural, I'll tell you straight: the honest thing is to have a surveyor or the building's architect assess it before covering it up, because painting over a deeper problem only hides it. I'll happily repair and paint cosmetic cracks (as part of flat painting or wall smoothing); with structural ones I'll point you in the right direction.
Want the exact price for your project?
I will come and see it with no obligation and give you a fixed quote, free and the same day. You deal directly with me, no middlemen.
FAQ
- Do fine cracks come back after painting?
- No, if they're repaired properly: open, clean, fill (with flexible filler on joints that move), sand and prime. They only come back when paint is slapped over them without repairing.
- How do I know if a crack is serious?
- Keep an eye on wide, stepped or diagonal ones, the ones that grow, and whether doors start to catch. When in doubt, better to have a surveyor look before covering it; I'll tell you honestly when I see it.