Repair methods
Epoxy crack injection
The contractor wants to inject epoxy into my foundation crack. What does that do?
Epoxy injection forces a rigid resin into a crack under pressure so that it fills the full thickness and bonds the two faces together. The intent is structural: to make the cracked section behave more like uncracked concrete.
It is a real and appropriate technique in the right circumstance, and the circumstance is narrow. Because the cured resin is rigid and strong, it needs a crack that has stopped moving — otherwise the concrete simply cracks again beside the repair.
What the method is
Ports are fixed along the crack and the surface between them is sealed. Resin is injected under pressure, travelling through the crack until it appears at the next port, filling the section rather than just the visible face.
Cured epoxy is typically strong and rigid, which is what allows the repair to transfer load across the crack rather than merely closing it.
Because it fills the full thickness, it also stops water — but water exclusion is a by-product here rather than the design intent.
What it does not do
- It does not tolerate movement. In a crack that is still moving, expect new cracking adjacent to the repair.
- It does not address why the crack formed. Injecting a crack caused by ongoing settlement or soil pressure leaves the cause untouched.
- It does not work well in a wet crack, since water interferes with bond, which is a practical constraint on active leaks.
- It is not a substitute for an engineering assessment where a wall is bowed, displaced, or cracked horizontally.
When professional evaluation matters more
- The wall is bowed, displaced, or cracked horizontally — an engineer's assessment should precede any injection
- The crack is measurably moving
- The crack is actively leaking, which affects both method choice and achievable bond
Questions to ask whoever comes out
- Why epoxy rather than polyurethane here, given what this crack is doing?
- How have you established that this crack is no longer moving?
- Has an engineer assessed the wall, and does this scope come from their report?
- How will you know the resin has filled the full thickness rather than just the face?
- If the crack reopens beside the repair, what does that tell us and what is the next step?
Where estimates for this commonly differ in scope
These are the places two prices for apparently the same work stop being comparable.
- Structural bonding and water exclusion are different goals achieved by different resins. An estimate should state which is intended.
- Whether the cause is being addressed by anyone is frequently outside the injection scope entirely.
- Warranties may cover leakage, adhesion, or neither, and the difference matters.
Professional evaluation is worth arranging
Conditions in this band can be associated with causes that a photograph cannot separate. Someone who can see the site is better placed to say which.
Who tends to do this work
- A concrete repair specialist
- A licensed structural or geotechnical engineer
- A waterproofing contractor
ConcreteOwner does not inspect, certify or approve contractors. This describes which trade usually holds this work, not a recommendation of anybody in particular.
Common questions
Is epoxy injection a structural repair?
It is intended as one — a rigid, strong resin bonding the crack faces so the section carries load across the crack. Whether it is the right structural repair for your wall is a question for someone who has assessed the wall, because the technique assumes the movement that caused the crack has finished.
Epoxy or polyurethane for my foundation crack?
Broadly: epoxy is rigid and aims at structural bonding on stable cracks; polyurethane is flexible and aims at stopping water in cracks that may still move or that are currently wet. Which suits your crack depends on whether it is moving and whether it is leaking, which is why those two observations are worth establishing first.
Will epoxy injection stop my leak?
It can, because filling the full thickness closes the water path. The complication is that epoxy bonds poorly in the presence of water, so an actively leaking crack is a difficult candidate. Where stopping water is the actual goal, a flexible resin designed for wet conditions is often the better tool.
Where to go next
What drives the cost
Methods that may apply
Want a straight answer about epoxy injection?
Both decision tools are free and need no contact details. If you would rather have somebody local look at it, you can ask us to review whether we can match you — and we will say plainly if we cannot.