Finding a crack at home is always disturbing. Doubts arise: will it be serious? Will the structure be damaged? Fear turns up even when it comes to a new home. What should we do?

Our first advice is to keep calm. Not all cracks in our walls and ceilings have to entail gravity. The second recommendation is to tell a professional because, sometimes, just with a quick overview is enough to make a first assessment.

Is reasonable to think that thinner the cracks are, the less important they are. That’s right, in fact, it’s even normal that in new homes there are some thin cracks on the walls caused, as commonly said, because of the house settlement on the land. If we want to be more precise with words we should use is that there’s been a deflection of the slabs.

Something very different is if, instead of being a thin crack, we can get into the crack a pencil or finger. In fact, from 0.5 millimeters thick we start to stop talking about fissure and we refer to crack. There are legal limits for ‘building settlement’ and it would be necessary to check whether this is really the cause or not. An architect will be able to tell us if the problem lies in differences on levels in the settlement, that can be a serious problem.


The causes of the bad news, can be either because of aesthetic impact or, even worse, because of the security they entail, are very diverse. Among them, we could highlight:

  • Poor plasterwork: This is the one, assumed that cracks appear, we all prefer, because does not entail great cost nor security risks. This problem is due to poor application of plaster or to the fact that too much was used, for example.
  • Overloads: This is the other side of the coin, one of the most serious problems, because it means that the house is badly designed from the beginning and the house withstands higher weight than what the foundations are capable of supporting.
  • Hygrothermal stress: Changes in temperature and humidity have an effect on construction materials, which expand or contract and as a result, can cause cracks that should not concern us too much.
  • Poor quality materials: Sometimes the poor quality of the elements used for the construction of the house can cause this damage, therefore, the criterion of a professional will determine whether, if in addition of being an aesthetic problem, it entails a security risk.

Differences between walls

Another important element when assessing the severity of a crack is in which of the walls appears. In this sense, we will distinguish between a partition-wall that separates a room from another or a concrete load-bearing wall. The causes of cracks on a partition wall may appear due to poor quality of joint materials or from the plaster that has not been correctly applied.

However, if the crack is on a load-bearing wall, it is imperative to find out if is due to structure problems. In the same way, we will not only look at the walls, but also at other structural elements, such as columns or beams.

At the same time, cracks in masonry and ceilings should warn us and we should urgently seek for professional advice.

Once the cracks are identified, starts the repairing works and at this point we have to differentiate between two types of cracks. If they are active cracks, they are still growing, it is not advisable to repair them because they will prevent us from correctly diagnosing their origin and, in addition, all the work would have been for nothing because they will appear again. It is important to survey the development and speed of active cracks.

If the cracks are stable over time and are superficial, the solution is simple: just prepare the surface to apply the filler and a new coat of paint.

Regarding the most serious cracks, it will be necessary an expert to assess whether it is necessary to apply corrective measures to the structure before face washing our walls and ceiling.