A straight hairline crack that follows a drywall seam and has not moved is usually cosmetic. A crack that comes with sagging, staining, or a widening gap is worth a professional look. Here is the quick self-check we use.
Most ceiling cracks are cosmetic. A thin, straight line along a taped seam usually comes from seasonal movement or from joint compound shrinking as it ages, and we can re-tape and finish it in one repair. Spiderweb or map-pattern cracks in an older ceiling are usually surface-level too. A crack needs a closer look when it comes with other signs: a section that bows or sags, a gap wide enough to slide a coin into, a brown stain along the line, or a crack that reopens in the same place after it has been patched. Any of those means something behind the surface is moving or getting wet, and painting over it will only last a few months. If your crack is straight, thin, and not changing, it is almost certainly a cosmetic repair. If it is getting wider, longer, or stained, send us a photo and we will tell you what we see.

