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The Cost and Process of Crack Injection

Sam Rathbun - ECP Business DevelopmentThis article was shared with ECP from our very own Sam Rathbun, one of our leading waterproofing experts. Check back in the future for more articles from Sam and stay in the know on waterproofing problems and solutions.

Walking down stairs to notice that you have water seeping in through a crack in your wall is an awful feeling. Fear not though, as it’s not the end of the world. Many cracks can be injected and sealed with a polyurethane foam. Crack injection is a fast repair and the cost is minimal. The cost is usually only a few hundred dollars depending on the size and length of the crack.

Injecting a crack in your basement wall

  1. First you will apply the ports over the crack, it is how the polyurethane is transferred into the crack. They are placed approximately every 10 inches starting at the bottom of the crack working your way up.
  2. Next you will apply a “surface seal” to the wall. Most “surface seals” or “epoxy pastes” will set up in 30 minutes (hence the quick repair time).
  3. Once that has set up and cured, you will then injection the polyurethane into the wall. Starting at the lowest port on the crack and leaving all ports open, you will inject the polyurethane until it starts oozing out of the port above it. Once it starts oozing out, plug the port you are on and move up to the next one.
  4. Repeat this process until you have fully filled your crack.
  5. After the polyurethane has set up for around 24-48 hours you can knock off the ports with a hammer.

When NOT to use crack injection

There are two very import notes you must know though. NEVER let someone tell you that it is a promising idea to inject your crack if you have a block wall. Because the blocks are hollow there is no way to ensure that the polyurethane will set up where it needs to be. There are other ways to seal cracks if you have a block wall and unfortunately the best way is the most expensive way, and that is from the outside of the foundation.

Epoxy Injection vs. Polyurethane Foam Injection

The second note is that, unless you are stabilizing your foundation with piers, do not use a structural epoxy resin to inject the crack with. A structural epoxy resin is what it sounds like, it is used in conjunction with structural repairs. It is a brittle epoxy designed not to shift or move. A polyurethane on the other hand will set up with a foam like property. This is designed to bend and move with the crack. If your house starts to settle a little more after you inject the wall, the foam will shift with the crack preventing unwanted water from intruding into your home.


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