What's the best approach to repair a wedge/corner crack in my foundation?

Question

I've got a wedge/corner crack on one corner of my foundation. I'll try to post a picture of it as soon as I can, but here's a sample image of what I'm talking about:

However, my crack is more complex. There are actually two pieces. The upper piece looks like the one in the picture above, and the lower piece looks like a mirror image, such that the two broken pieces of the corner are wedged against one another at their tips.

This makes repair problematic, since the two pieces are wedged against one another so well that I can't pull either free to put any kind of repair compound on the back side of the cracked pieces. If I simply fill over the crack, I'm worried that it won't be strong enough to hold the pieces to the foundation, and it will just crack again.

How would you suggest that I should proceed? I'm thinking I have these two general options:

• Try to inject some repair compound as deep into the cracks as I can, hoping that I'll get it deep enough to bond the pieces to the foundation.
• Do my best to remove the pieces so that I can apply repair compound directly to the back surface, even if that means doing more damage to the pieces themselves.

Answer 1

I worked concrete one summer while I was in high school, but I'm no expert and it was a long time ago. That being said, here's what I would try:

I'd give both of your solutions a shot first. However, if you end up completely destroying the two chips, I'd try to pour a new corner. Drill two holes into the corner of the foundation and dowel into it with a few inches of 3/8" re-bar. After you've hammered in the steel, form up the corner and pour the concrete.

Also, this forum includes discussion about how to repair similar cracks.

This website also explains a bit more about this type of foundation crack:

Brick that is laid directly in contact with concrete foundations can cause angular cracks like this in the top 12 - 16 inches of a foundation. These cracks are caused by the brick expanding and pushing the outer corner of the foundation with it. The cracks are not major structural problems.

It is often pointless to repair them as the next time it gets hot, a crack will likely appear in your repair material.