What is an epoxy crack injection?
An epoxy crack injection is a pressurized injection of epoxy resin (an epoxy specifically for concrete crack repair) into a foundation crack from the inside to the outside. The epoxy fills the crack through the entire foundation wall thickness, right to the outside. Then, the epoxy cures (usually 3-5 hours at 77°F). After curing, the foundation crack no longer exists because the epoxy has completely filled the foundation crack and bonded the two sides of the crack together with a bond strength exceeding the strength of the poured concrete.
How an epoxy crack injection works
The principle behind the injection is relatively simple – you contain injected epoxy in a poured concrete foundation crack until the it has fully cured.
Injection epoxy is a 2 component epoxy, meaning that the resin is blended with a hardener. The blending of the epoxy and the hardener is accomplished by pressurizing the 2 fluids through a static mixer before it is injected into a crack.
Fundamentally, the injected resin is confined within a foundation crack by the soil against the exterior side of the wall and a fast setting epoxy paste applied over the crack on the interior side of the wall.
Why the epoxy injection is desireable
An epoxy crack injection accomplishes two important goals:
- It permanently repairs a crack in a poured concrete foundation; and
- It permanently prevents a basement crack from leaking.
A crack injection using epoxy is a proven, permanent concrete crack repair that is extremely reliable due to the injection methodology associated with this type of injection and the properties of epoxy resins in general.
An epoxy crack injection is a foundation crack repair method suitable for poured concrete exclusively. It is not suitable for repairing cracks in concrete block foundations.
What an epoxy crack injection costs
Many companies do not offer epoxy crack injections as part of their service offering. Companies with expertise in pressurized injection will offer both epoxy and polyurethane crack injections. The price range for epoxy crack injections among waterproofing contractors is $350 – $525 per crack as of December 2016.
When comparison shopping for an epoxy injection, what matters most should be:
- The skill, experience and work ethic of the technician tasked with the injection; and
- The technician’s access to several viscosities of epoxy to ensure that the injected resins do not bleed into the soil outside.Our customers have reported over many years that they generally received what they paid for; in other words, people who paid the lowest price generally received poor service, no warranty service, or the repairs did not stand the test of time.
Do you have to inject with epoxy to properly repair a crack?
With respect to concrete crack repairs, cracks in poured concrete can only actually be “repaired” using epoxy resin. Any other repair method is either a waterstopping repair (such as a polyurethane crack injection) or some form of patch. The old fashioned crack repair method of “V-ing” out a crack and putting hydraulic cement in the “V” is actually an unreliable way of plugging a crack. Without pressurized injection of a resin into a foundation crack, it is not possible to fix a crack through the entire thickness of a basement wall. Both epoxy and polyurethane pressurized injections fill cracks through the thickness of a foundation wall.
Claims about epoxy crack injection that don’t matter:
Waterproofing contractors that do not offer epoxy crack injection often claim that the material injected into a crack must be flexible; therefore, they claim that epoxy is inflexible and that a crack must be repaired by polyurethane injection or external excavation. It is true that epoxy is inflexible; however, how flexible is a concrete foundation to begin with? An epoxy injection will restore a foundation wall to its original condition before it developed the crack.
If another crack develops in close proximity to an epoxy crack injection, the problem you have is not with the epoxy injection. Rather, the foundation is moving and has created a new crack because the bond of the epoxy crack injection is so strong. The second crack is attributable to foundation settlement which is a much more serious problem than the development of another crack in your foundation.
Waterproofing contractors that claim that an epoxy crack injection does not work are not being honest. Over the past 14 years our company has had 2 callbacks related to epoxy crack injections. Those contractors who make these claims fall into 1 or more of 3 categories:
- they do not offer the service
- they cannot reliably perform crack injections (they do require quite a bit of skill and perseverance); or
- they prefer to excavate so that they can charge you 3 times what a crack injection costs.