Therefore, you can’t just ignore cracks in a foundation or concrete slab. Filling in these cracks and stopping them from spreading is essential to preventing serious structural issues in your home. This may seem like a tempting thing to do however, you should allow foundation professionals to inspect and repair your foundation if you are able.

Size does count

The real test of any crack is its size and placement. Smooth, even hairline, cracks are usually not serious and a quick repair is all that is needed to prevent them from turning into something more serious. Any crack with an accompanying slant or bulge–in any direction–is serious. The same goes if the crack is large enough to put the tip of your pinky into or if it’s leaking water. These types of cracks need to be assessed by an expert before any repairs can be done. In this case you would call a foundation expert.

When horizontal cracks are a problem

Horizontal cracks are most common in concrete block and brick foundations, but they can also show up in poured concrete foundation. Usually they are the result of frost damage after freezing temperatures shrink the concrete, but they are also caused by excessive pressure on the foundation from wet soil.

Long, horizontal cracks extending the full length of any outside wall should be investigated closely. A bulging crack can indicate a wall sliding off its footing or other stresses on a supporting wall.

Those who understand the relationship between soil and foundation stability seem to think that over watering the soil is the leading cause of damage. This isn’t entirely true. Though water causes soil to expand – and extreme heat will shrink the soil – the differences typically aren’t enough to cause significant cracking. Identifying cracks in your foundation is important. These are symptoms that tell you something much larger is occurring somewhere beneath the surface. However, you shouldn’t assume that cracks will help you identify the source with 100 percent accuracy.