Although a concrete foundation is a solid structure, cracks can still appear over time. Some occur due to exposure to extreme weather conditions, while others may occur due to natural soil movement or mechanical overload.
Whatever the reason for their presence, cracks must be repaired to avoid any water infiltration or the appearance of mould. To this end, several sealants exist to repair openings in concrete structures. But are you familiar with the different resins on the market and their specific properties?
One concrete structure, two resin choices
Two types of resin are generally used to fix cracks: polyurethane foam and epoxy. Both are two-component formulations. The question of which product works best depends on the type of crack or seal and the conditions at the time of repair.
Polyurethane foam to the foundation’s rescue
To repair the grooves in your concrete foundation, you can start with polyurethane foam. Polyurethane foam is a flexible product that responds well to crack movement and moisture. This type of resin expands during injection, reducing the amount required to perform the repair if the opening is wide. Wet or leaking cracks respond very when this foam is used.
There are many advantages to using polyurethane foam to repair cracks in concrete structures. First, it is more affordable than epoxy, which we will see below. In addition to being easy to use, the foam quickly treats the crack. Since foam expands when applied, it corrects deep structural problems.
Despite its many advantages, polyurethane foam is not flexible. This means that it can tear under high tension. You will therefore have to repair the crack again. However, to prevent the crack from expanding, carbon fiber staples can be used for reinforcement.
Epoxy steps into the breach
Epoxy is another effective solution to repair concrete foundation cracks. This low viscosity resin is well suited for repairing thin structural cracks. Unlike polyurethane foam, epoxy remains in a liquid state during application, which allows it to enter all gaps. Most epoxy products harden completely in three to four hours.
Epoxy provides a strong bond that welds cracks together and restores the strength of the structure. Also, in most cases, a crack fixed with epoxy will not fail. In addition, an epoxy-filled concrete crack will not move due to temperature variations and wet and dry seasonal cycles.
Disadvantages that bring the house down
As mentioned above, epoxy is more expensive than urethane. Moreover, it will be less effective if the crack is not dry. In addition, if the bond is not strong enough or fails, it will be impossible to reuse this resin in the break, since epoxy won’t fill the entire length of the crack due to obstructions. New material will therefore be required.
Which resin is best for a concrete foundation?
In the end, which resin is best to repair a crack in a concrete foundation: polyurethane foam or epoxy? The properties of the crack should determine the product and method. Of course, not everyone can make this crucial diagnosis. If you need to properly fix a crack in a concrete foundation, contact us today!