Due to the brittle nature of concrete when subjected to high tensile stress, it is common for cracks to appear as a result. This natural phenomenon in the life cycle of a structure is not a sign of a design defect. Ground movements due to the effects of frost or water are usually the cause.
In order to properly seal cracks, a number of factors such as surface type are taken into account. Choosing the wrong product for concrete foundations can lead to serious problems. The type of sealant also depends on the method used. Repairs can be carried out from inside the building or from outside depending on the size of the crack.
Choosing the sealant for a concrete crack repaired from the inside
This repair technique is faster to implement and has many advantages. It consists of a high-pressure injection of resin into the crack, making it the most cost-effective and least constraining solution. It can be carried out under all conditions and makes it possible to use an effective sealant to seal a more or less narrow concrete crack.
Polyurethane offers great flexibility and is an ideal sealant for the residential sector. Its high pressure injection can be carried out from the inside in all seasons and even in the event of water ingress. The polyurethane foam penetrates and adapts to the shape of the crack, benefiting from an expansion of seven times its initial volume depending on the thickness of the wall. This fast-setting concrete crack sealant features elastic properties and a relatively low cost.
Working like a weld, epoxy is very effective because of its powerful properties. It seeps into the crack like a glue and hardens in three or four hours. An epoxy resin interior repair is ideal for large buildings and limits new movements due to weather conditions. Using it as a sealant to repair a concrete crack is more expensive than polyurethane foam, but allows the structure to regain its full strength. However, it is not recommended in a humid environment prone to seepage.
A sealant for repairing a concrete crack from the outside
If the crack is too large, it is best to work from outside the building. Excavation work is therefore required to reach the impacted area. After it has been cleaned, a V-shaped opening in the outer crack is made to apply the cement. The sealant you select is then used to fill the concrete crack, before covering it with a waterproofing membrane. This is a very reliable solution, but much more expensive than working from the inside.
Get help from a specialist to make sure you are using the right sealant
When choosing a sealant to fill a concrete crack, you need to carefully consider its properties. A specialist will be able to select the most suitable method and the right product.
At Foundation Crack Expert Group, we have extensive experience in foundation crack repair. We welcome you to provide us with more details about your situation using our free quote form so that we can provide you with personalized support.