Understanding the Types of Foundation Cracks

Do you have cracks in your foundation? If so, it’s worth taking a look at them to make sure they don’t signify a larger problem that will require repairs. It is a good idea to determine the severity of the cracks you need to examine the shape and the direction of the cracks. Depending on how the crack appears, it could point to unique issues that need to be addressed. Here’s more information:

Horizontal Cracks

These types of cracks run horizontally across the wall of the foundation. These cracks are usually considered to be serious and could signify a larger issue. Horizontal cracks are most common in establishments with poured concrete foundations, brick foundations or concrete block foundations.

Common causes include heavy rainfall, which is followed by very low temperatures that increase the hydrostatic pressure on the foundation causing the foundation walls to bow inwards. Another common cause is the anchoring of a set of steps to the foundation walls resulting in excessive pressure to the foundation.

Vertical Cracks

These are cracks that run straight up or down. They can also take on a slightly diagonal shape of no more than 30 degrees. They are fairly common and they don’t always signify a larger problem. Typically, they begin to form about one year after the foundation was created.

Vertical cracks are formed when the foundation concrete settles and some tension ebbs away. In some cases, they are as a result of heavy rains that exert significant force on the foundation. Fortunately, these cracks are just superficial and don’t usually threaten the foundation. They are also the easiest and least expensive to fix. Since the cracks are usually less than 1/16 of an inch, an epoxy material is injected into the cracks to maintain a tight seal.

Diagonal Cracks

Diagonal cracks run at an angle of 30-75 degrees across a wall. The cracks are usually broader at the top but become narrower as they travel downwards. They permeate through a house’s damp-proof course (DPC) barrier all the way to the foundation.

These cracks appear when the supporting soil becomes unstable, usually through contraction caused by dehydration or through excessive rain. This causes the foundation to become uneven and taper off on one side. This is why the cracks tend to be wider at one end and thinner at the other. The best way to deal with diagonal cracks is to first understand the root cause and address it.

Stair Step Cracks

Stair step cracks, just like diagonal cracks, occur due to the differential settling of the base foundation material. However, unlike diagonal cracks, these cracks form at the end of a wall and shoot upwards in the form of a staircase.

If the cracks appear in the mortar joints they are not serious and can be patched up just like diagonal cracks. On the other hand, if they result in the displacement of bricks, they need to be evaluated by a professional to determine the extent of the problem.

Understanding the different types of cracks should help you determine the nature of the problem your foundation faces. However, it is always advisable to consult an expert to ensure your home’s structural integrity is not at risk due to misdiagnosis.

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