Common Types of foundation Cracks

Cracks in the foundation occur in different sizes and shapes. It is not uncommon to have gaps in the old or new construction near windows, walls, floors, footings, slabs, etc.

Most of the cracks are due to settling, premature drying, etc. However, it is not a concern; the primary concern is the type of crack to find the correct repairing solution.

In this article, you will get to know about different sorts of foundation slab cracks occurring to find the best repairing solution possible.

Premature Drying Cracks

Whenever a concrete slab or the top layer loses moisture faster, it can cause cracks. Crusting cracks results during the process of stamping when the top layer is dried to embed patterns.

Crazing cracks take place when the top layer of the slab loses its moisture naturally. This crack takes the shape of a spider web. These types do not appear appealing, but they are harmless for the slab’s structural strength.

Horizontal Foundation Crack

It may occur and lead to a severe issue. This sort of crack happens due to hydrostatic pressure from the exterior walls and can cause a failure in the foundation.

Most of the foundations are built for handling the water and soil pressure. Extra pressure because of flooding or heavy rains can cause severe cracks that require quicker repair.

Stair Step Cracks

Block foundations lie flat to stair-step cracks that take place along mortar joints. These pose a severe danger to the integrity of the basement foundation. There are two of the common causes of stair-step cracks as –

  • Foundation sinking or settling in one area
  • Moisture problems in the exterior of the foundation

Note – You can call for expert inspection and repair solutions whenever needed.

Plastic Shrinkage Cracks

When you observe concrete in its plastic state, i.e., when it is full of water before hardening. And whenever water leaves the slab, it leaves behind the large voids in between the solid particles.

Those empty spaces make your concrete weaker and lead to cracking. This sort of cracking takes place frequently, which is called plastic shrinkage crack.’

Plastic shrinkage cracks occur anywhere in the wall or slab where they almost locate at the corners pointing into the slab. It may also be discovered in the middle of the concrete slab, such as drains, pipes, manholes, and plumbing fixtures.

They grow narrow with time in width. So, it is vital to remember that plastic shrinkage cracks do not only exist on the surface. It extends throughout the overall slab thickness.

Hairline Cracks

These types of cracks happen in the concrete foundations as concrete cures. Hairline cracks do not lead to problems of foundation stability but can result in leakage issues.

If the damage takes place in a short time after pouring the concrete foundation, concrete may have been mixed quickly or poorly. The hairline crack appears frequently in the center of the walls due to the excellent stability of wall corners.

Vertical Cracks

In foundation walls, vertical cracks appear less severe and do not cause any structural threat. They are commonly found in the poured foundation that runs straight up and down your wall.

Vertical cracks are the most common type of crack in basements which are caused due to the settling overtime of the foundation.

Note – If moisture is absent and you can’t fit a quarter in the crack, there is no immediate risk. You can repair this type of crack with epoxy injection.

Diagonal Cracks

Another everyday sort of crack that you may find out is the diagonal crack. It runs along the basement or foundation wall at an angle of 30 to 75 degrees.

The diagonal crack may be the thin hairline crack but will be wider at one end than the other. Diagonal cracks are due to differential settling of the foundation.

This sort of uneven tension causes diagonal cracks. You are settling results from the house built on a hill because of the contraction or expansion of soil.

Overloading Slab Cracks

Concrete is a strong building material, but it has limits. Locating excessive amounts of weight and loads on the top of the slab made up of concrete can lead to cracking.

Whenever you say that a concrete mix has the strength of 2000, 3000, or 5000 PSI, it refers to the pounds every square inch. After the heavy snowmelt or rain when the ground is wet and soft below, massive weight on the slab can press down the concrete, leading to slab cracks.

Settlement Cracks

This type of crack may appear when the underlying ground has not been prepared or compacted, or it may also be due to inconsistency of subsoil.

The settlement crack occurs as the random crack where the soil of the subgrade was found uneven after pouring concrete. Settlement cracks are more extensive at the top in comparison to the bottom. It is usually continuous that may appear multiple times in a wall.

Expansion Cracks

Concrete slabs tend to expand outwards when they are subjected to heat. Small space to grow can lead slabs to build cracks. Expansion cracks occur during the planning and concrete construction stage of the structure. They are inserted in between slabs that can absorb pressure from expansion.

Heavy Cracks

Another crack that happens because of temperature is a severe crack. Serious cracks occur because of extreme cold weather that leads to the condensation of the slab.

The slab expands back to the standard shape. The change in shape causes the development of serious cracks.

Structural Cracks

It happens in the residential foundation that results from settlement or horizontal loading. Most of the structural cracks result from the applied load. They are common in the block foundation walls.

Floor Cracks

Floor cracks are relatively common and usually not stressful on the structural level. They must be repaired and fixed to prevent common problems such as damage, moisture, and insects from seeping.

Whenever floor cracks leak, it is caused by hydrostatic pressure or a high water table. Thus, sealing the crack will lead to those problems. So, fixing the source of such issues prior is required.

Final Words

Knowing different types of slab cracks may help you discover the severity of the damage to your foundation. However, any cracks you find in your foundation must be taken seriously and professionally inspected and repaired.