As we all know, concrete is the most durable and long-lasting material to build any structure for your home or commercial space, especially when installed properly.
However, it is crucial that concrete contractors follow proven methods and a set of rules when placing concrete to achieve a strong, long-lasting, and crack-resilient structure.
Why Do Concrete Walls Crack?
There are several reasons why concrete cracks. Below is some useful information that might help you understand why cracks are starting to show on your concrete walls:
Excess water in the pre-mixture
For concrete to reach its optimum strength, only an adequate amount of water is needed.
However, in residential construction, a significant amount of concrete is added to the bulk of the mixture. To make the installation process easier, water is injected. Because of this, the concrete’s strength diminishes.
One thing you need to know about concrete is that it shrinks as it cures and hardens, thereby causing it to crack. This is due to the evaporation of the excess water in the mixture.
The concrete experiences stress due to this shrinkage, literally tearing the slap apart. These stresses ultimately result in cracks.
Fast-drying of the concrete
Because concrete slabs are fast-drying, their likelihood of cracking is greatly increased. Water is necessary for the chemical process that turns concrete from a liquid state into a solid.
After the concrete is poured, a chemical reaction called hydration happens for days or weeks.
By adequately curing the concrete slab, you can ensure the water required for this reaction is available.
Lack of control joints
Control joints are devices that can help crack the concrete where you want it to. The joints must match the slab’s depth and not exceed approximately two to three times the concrete’s thickness.
Wrong concrete strength used
Concrete comes in a variety of strengths. You must always check the strength of the concrete you are pouring.
What are the Different Types of Cracks in Concrete Walls?
Certain cracks need more attention than others. The following are the common types of cracks:
- Hairline cracks
If you see little surface cracks that get worse over time, they should be repaired as they can become hazardous, gather dirt, and be unsightly.
- Settlement cracks
Settlement cracks occur when a portion of the concrete settles due to improperly compacted earth beneath the slab.
- Shrinkage cracks
Proper joint location can minimize or completely avoid shrinkage cracks. This type of crack usually happens during the curing process of the concrete.
- Structural cracks
Concrete must be repaired or replaced when structural cracks occur, especially if they become larger or extend through the slab.
What are the Six Effective Ways to Repair Concrete Cracks?
Depending on the size, position, and severity of the cracks, there are a variety of concrete block wall repair techniques you can use to repair your concrete, which are as follows:
Crack injections
There are two types of crack injections: epoxy and polyurethane injections.
Epoxy compounds have high compressive, tensile, and bonding strengths. This type of crack injection is best for narrow and non-structural cracks because epoxy can flow easily and penetrate through cracks as narrow as 0.05 mm.
The downside of this method is that it has a low tolerance for harsh weather conditions. They do not do well on wet surfaces.
On the other hand, the polyurethane injection is also ideal for non-structural cracks in wet and dump areas.
Polyurethane expands approximately 2 to 40 times its original volume and can seal and fill cracks completely. It’s also fast-setting.
Routing and sealing
This type of restoration works well for non-structural and broader cracks. To fix the concrete wall cracks, this methodology entails routing or enlarging the original crack and sealing it with an appropriate sealant.
Because of its ease and accessibility, this method is quite popular.
Control joints
In some circumstances, you might need control joints, such as expansion joints and movement joints, to fix the cracks.
This methodology is best for when the crack is actively growing or persistently recurs even after repairs.
Control joints are sometimes necessary to provide breathing room for the concrete components. For example, if a concrete block is cast without an expansion joint, it will most likely crack.
Patching or filling
One of the easiest ways to fix hairline cracks is to patch them by using patching solutions such as hydraulic cement or vinyl concrete patches.
If you want the best results, you can opt to use non-shrink concrete grout, as it does not alter in volume once it dries.
Check out our concrete masonry services here for more details.
Stitching or cross-stitching
Stitching or cross-stitching is the way to go if you want to restore the tensile strength across a crack.
This method involves drilling holes on both sides of the crack and installing metal staples or sewing dogs. Once you’ve finished sewing, you can use an epoxy resin-based bonding method or non-shrink grout to secure the stitch or sew.
The stitching dogs should be placed in a way that disperses the tension away from the cracks. For this reason, it is recommended to use stitching of various sizes and adjust and vary the placements.
Drilling and plugging
This technique involves drilling a hole down the length of the crack. It is best for vertical fractures that follow a straight line.
The hole must first be cleaned and filled with epoxy or non-shrink grout.
The grout key prevents the concrete portions on each side of the fracture from traversing. Moreover, it stops heavy water from seeping through the cracks.
How Can You Prevent Concrete Cracks?
Regular maintenance and repair are among the best strategies for controlling cracks in structures. To detect cracks early enough, regularly check your concrete walls for indications of cracking, such as visible holes and water leaks.
Also, ensure that you examine the source of the cracks before attempting to fix them. Address the underlying causes, such as settling or moisture ingress, to prevent cracks from recurring.
Always ask the advice of a structural engineer or a qualified block wall masonry contractor for major structural problems or substantial damage.
Solid Masonry Contractors is a team of experts who can help you evaluate the issue and suggest the best course of action for repair.
Call us today and get a FREE quote!
