Most cracks in a home are in the plaster or the paint and do not compromise the structure. The ones that matter give clear signs: they are diagonal or stair-stepped, go through the wall, are more than one millimeter wide, keep growing, or appear in beams, columns or slabs. If you see any of them, ask for an inspection.
The ones that are usually harmless
Hairline cracks, under 0.3 mm, in a web pattern on the plaster, or straight cracks where a wall meets a column. They are almost always mortar shrinkage or temperature movement, and a good patch and elastic paint take care of them.
The ones to have checked
Diagonal cracks running from the corners of doors and windows, or cracks stepping down along the block joints, usually point to foundation settlement. Horizontal cracks at the base of walls or in beams can point to lateral pressure or overload. In beams and columns, a crack that follows the line of the steel and comes with rust stains points to corrosion of the reinforcement. Doors that suddenly start to stick, floors that go out of level and cracks that open after an earthquake are also reasons to consult an engineer.
How to tell whether a crack is growing
Mark the ends with a pencil and write the date beside them. Take a photo with a ruler or a card next to the crack, for scale, and repeat it every two weeks. If it gets longer or wider, it is active and needs a diagnosis. A crack that does not change in two or three months is usually stable.
On the coast, salt air
In Barranquilla, Cartagena and Santa Marta, the sea breeze carries chlorides into the concrete. When they reach the steel, it corrodes, expands and breaks the cover from the inside. Those cracks follow the bars and usually come with brown stains. We cover it in Chlorides and reinforcement.
What an inspection does
An engineer looks at the cracks, their pattern and their history, and tells you whether there is an immediate risk. If needed, the diagnosis continues with testing: concrete cores, ferroscan to locate the steel, carbonation depth and chloride content. That tells you the cause and what the repair will cost. See our assessment and retrofit service.
Frequently asked questions
When is a crack dangerous?
When it is diagonal or stair-stepped, goes through the wall, is more than one millimeter wide, keeps growing, or appears in beams, columns or slabs.
How do I know whether a crack is growing?
Mark its ends and the date with a pencil, and photograph it with a ruler beside it every two weeks. If it gets longer or wider, it is active.
