No matter how sturdy a concrete foundation is, it can develop cracks or fissures. The cause of unwanted cracks in concrete can be due to prolonged exposure to natural environmental forces such as:

  • Repeated wetting and drying from rainwater seepage
  • Topsoil and subsurface earth layer erosions
  • Naturally occurring foundation settling
  • Damage from unchecked tree root encroachment on concrete slabs

To prevent extensive damage and higher maintenance costs, it is important that you monitor cracking and contact a professional in the case of widespread cracking and settlement. Early detection and repairs will ensure that concrete slab cracks don’t necessitate costly foundation repair methods.

Is a Crack in a Slab Foundation Bad?

Cracks in a concrete slab can be a sign of structural problems or superficial. Structural cracks in cement slab foundations can adversely affect various parts of the overlying structure. In severe cases, disruptions in slab continuity manifest as buckled walls with disfiguring cracks and crevices, leaning buildings, and broken up floors with uneven or undulating surfaces.

A cracked slab can pose a significant problem to the building and structures overlying it as they will develop distortions which translate into critical but unplanned maintenance expenditures.

hairline cracks in concrete slab

What Causes Concrete to Crack?

So, why does concrete crack? Various natural and artificial influences interact to cause concrete slabs to develop cracks. The following factors will determine the chances of cracks developing in a concrete foundation.

Poorly Constituted Concrete

The presence of surplus water in a cement mixture significantly raises the chances of a completed concrete slab developing cracks. The rapid evaporation of extra water from the concrete mix will shrink the drying solution leading to the formation of fissures or cracks in concrete floors.

Uneven Sub-grade

Before laying a concrete foundation, the soil surface or sub-grade is primed. It is vital that an even surface is achieved before pouring a foundation slab. An uneven or undulating surface increases the probability that the finished slab will buckle and break up as it dries.

Poor Concrete Curing

It has been established that rapid drying of concrete will cause cracks in floor slabs. Concrete curing is a process that allows water elimination in a controlled manner. If curing is improperly done, the water evaporation will leave hairline cracks in the concrete slab.

6 Types of Cracks in Concrete Slabs

Different types of cracks in buildings have been observed to develop over time regardless of the strength of the initial concrete mixture utilized in creating the foundation. These structural cracks in concrete slabs occur due to a combination of natural and artificial factors that are described below.

1. Settlement Cracks

Settlement cracks develop when the loosely aggregated soil beneath a concrete slab gets eroded or settles. Since the soil has settled some areas of the concrete slab are unsupported and can crack from stress. Further, tree root decomposition will create pockets of weakness below building foundations into which their concrete slabs will settle and develop areas of breakage.

Foundation settling cracks can be quite worrisome especially if the damage is extensive. In these cases, the affected foundation may need repairs.

2. Plastic Shrinkage Cracks

This type of crack occurs when water escapes from the exposed upper surface faster than the lower part leading to uneven drying of the concrete slab. Simply keeping the surface moist during the setting process can help prevent these types of cracks from emerging.

Also, chemicals that hinder rapid moisture loss can be applied to the surface of the concrete to slow evaporation and ensure a more even curing.

3. Heaving Cracks

Tree roots can exert significant amounts of pressure on structures blocking the path of their spread. Unchecked, these tree roots can extend beneath foundation slabs and disrupt them resulting in up-heaving cracks that elevate and break up the concrete slabs.

Tree root barriers can be a helpful measure for preventing this issue and prevent the soil under your concrete from losing moisture.

4. Pressure Cracks

When the weight-bearing capacity of a concrete slab foundation is exceeded, fine cracks may develop on the surface. Heavy vehicles and building fixtures are the main causes of pressure cracks. Typically, these types of cracks pose minimal risk to the overlying structures.

5. Crazing Cracks

cracks in cement slab foundation

These are tiny fissures that occur on the surface of a rapidly dried slab. These defects develop in a spider web or mosaic pattern. Crazing cracks pose little threat to the integrity of a foundation and don’t always require repair.

6. Crusting Cracks

Crusting cracks develop in concrete slabs that have been manipulated into shapes and patterns. Uneven drying of the wrought surfaces will cause fissures to form. Just like with crazing cracks, crust fissures do not require advanced repairs and can be fixed easily.

Contact URETEK for Solutions to Your Foundation Problems

URETEK Gulf Coast has remained dedicated to offering its clients the best quality plumbing, HVAC, and foundation repair in Houston for all types of private and public structures. Our foam foundation injection and pressed piling foundation repair techniques will guarantee that you get the most satisfactory results.

Contact our team today if you’re based in Houston and would like to learn more about our commercial and home services!