Concrete can last for hundreds of years, but small cracks, holes and extensive gaps may appear on the surface at some point. Suppose your patio, foundation walls, sidewalk or driveway have begun to age and have defects in their surface. In that case, you need quality fixing cracks in concrete. Even though you need professional help in some situations, almost anyone can handle minor defects.
What materials are used to fill or seal control joints in poured concrete slabs
Waterproofing cracks in concrete are carried out using a variety of materials. The best materials for this task are:
- ready-made plastic strips of control joints and other materials;
- sealant (most often polyurethane);
- semi-rigid crack filler based on epoxy resin;
- hydraulic cement;
- sealant based on polyurea.
When selecting the optimal material, it is worth making sure that it can bind to the sides of the defect, remaining flexible in any humidity and temperature conditions.
How to Prepare a Concrete Crack for Caulking
Concrete crack leak repair always begins with proper preparation of the work front. Typical preparation includes several steps:
- cleaning the crack – you need to altogether remove debris. For this, it is best to use a vacuum cleaner;
- preparation of the sealant – read the label of the composition and act under the manufacturer’s instructions;
- install a support rod if you are sealing an epoxy sealant expansion joint – you need to put a flexible filler in the form of a support rod to hold the sealant in the joint when it cures;
- apply sand as a crack filler (great for repairing a crack in the floor). It needs to be poured about 3/4 inch from the top surface of the floor;
- curing the sealant – while the composition will cure, you should not allow cars to move on the floor. You often have to wait 7 days until it is fully cured.
Effectiveness of polyurea for sealing control joints
Joints with concrete can be filled with compositions based on polyurea. This material has several advantages:
- resistance to moisture;
- high adhesion to the concrete;
- the ability to harden even in cold weather.
In addition, polyurea sealants can be used during the sealing of control joints in concrete, even if it is still wet. It has not passed a month to fully cure. The benefit of polyurea is that due to the reasonably decent flexibility of the material can cope with small seasonal or temperature shifts that could provoke new cracks when repairing defects with epoxy.
Peculiarities of crack sealing with polyurethane foam
Professional crack waterproofing can be carried out using polyurethane foam. The composition is injected under high pressure into the defect in this situation. A particular piece of equipment with a pump or a device similar to an automobile grease gun is used for this purpose.
Why it is worth using injection sealant for sealing cracks with polyurethane foam
Polyurethane foam is used in the following situations:
- It is not necessary to make structural repairs. It is worth sealing cracks from water or air leaks at that time.
- If the building still needs to give complete shrinkage and shortly may repeat the slight cyclic movement, which can cause cracks. Flexible polyurethane sealant, in this matter, is the best solution.
- It is necessary to seal a small crack. This material is easier to install and will cost less.
- You need to make the repair at home. Polyurethane sealant is easier to use than epoxy sealant.
- If you need to seal a large crack in a foundation wall. Sealants on epoxy can leak out, so it is worth using polyurethane foam.
- The crack is actively leaking. Polyurethane sealant will adhere perfectly to the surface, providing a quality seal.
Epoxy-based grout for filling cracks in concrete
If the defect is much deeper and more prominent, it is worth using a special sealant based on epoxy resin.
Why use an epoxy-based sealant
Epoxy sealant is worth using in the following situations:
- You need to make structural repairs. The strength of epoxy is more substantial than concrete. When properly mixed and applied, it will achieve high-quality repairs.
- A small crack needs to be repaired. Polyurethane foam cannot fill minor defects, which is perfectly coped with by epoxy sealant. If the crack is vast, it is worth taking a composition with high viscosity.
- It is required to create the smoothest possible surface.
What sealant to choose: polyurethane or epoxy
Many cracks in foundations and floors can be eliminated with the help of polyurethane or epoxy sealant. The epoxy sealant is often suitable for repairing small cracks that polyurethane foam cannot reach. The second option is the best solution for more significant defects.
Hydraulic cement for caulking cracks
Hydraulic cement is a water-resistant cement composition, which can be found on sale in dry form. To prepare it for use, you must mix it with water before the job. It is then applied (or troweled) directly into cracks in foundations and other surfaces.
As for the cost, hydraulic cement is cheaper than other crack repair materials. At the same time, this mixture has a significant disadvantage. It may re-crack as a result of shrinkage of the composition or a slight movement of the structure due to rainfall, soil pressure, and temperature variations. As for the advantages, with the help of hydraulic cement, it is possible to qualitatively seal the crack, even in the case of active considerable water leakage through it.
What tools are needed for the repair of cracks in concrete walls
Sealing cracks in concrete is carried out using a variety of instruments. Before proceeding directly to the case, you need to prepare the following:
- metal brush;
- mason’s trowel.
Repairing cracks in concrete in 4 steps
Structural cracks in concrete can lead to severe problems, so you should not ignore them. If you want to patch this effect, here’s a step-by-step guide on how to do it, consisting of 4 simple steps.
No. 1: Choose the right caulking product
Strange as it may seem, the concrete surface is not repaired with concrete. In this situation, particular repair compositions are used: sealants based on epoxy resin, polyurethane foam and other options. Depending on the complexity of the problem, you need to choose the best option.
No. 2: Purchase the necessary tools for repairs
When you have already decided what and how you will repair it, you need to buy all the necessary tools and compounds. You can do this in a construction store.
№ 3: Prepare the crack to be repaired
To prepare a crack for repair, you first need to take a small hammer and chisel to knock down the broken area’s loose, crumbling and cracked concrete. It is also worth digging a little deeper. Afterwards, washing the crack well and cleaning it with a metal brush to remove all the dust is necessary. Note that this process is quite messy and dusty. It would help if you covered the floor with a tarp before cleaning the crack.
No. 4: Caulk the crack with the material of your choice
Next, you can proceed directly to the caulking process. If using epoxy or latex, you should mix the compound according to the manufacturer’s instructions on the label. After using a trowel or trowel, apply the material to the crack, fill it completely, and level the surface. Before using a particular repair compound, it is necessary to read the instructions in detail, how to mix it properly, how to apply it and how long it takes to fully cure.