Seriousness of cracks in CBS

Okay, but look at it closely. Follow the arrow. If that corner sinks and rotates as illustrated, the crack will be wider at the top.

That would be complete separation of a section, the corner of a foundation requiring stabilization/underpinning. Movement. Off axis and Rotation.

The cracks starts somewhere doesn’t it? It does not wake up one day with complete separation of a section unless there is an earthquake, lol.

But, it could be heaving. I am not denying that.

But there is one interesting clue by the OP.

Everything has a beginning.
Don’t think 2D or 2 dimensional. Think 3D.
The detached concrete is separated from the main foundation, detached, and settling in the soil while rotating.

So, heaving or settlement?

I will say that I dont remember the last time I saw a crack that was wider at the bottom around here.

we have really stable soil here in the mountains of western NC.

What we also have is a lot of homes built onto a steep hill…and inevitably they need to end up putting part of the foundation onto non virgin soil on the downslope. Not all the time…but it happens.

I’ve had many homes that were leaning significantly down the hill.

every serious crack I see around here is wider at the top.

no idea the significance of all that…just what Ive observed around here.

2 Likes

Neither have I. Must be a Quebec thingy. LOL

4 Likes

I am not going to say any more. Dam when I can not explain differential settlement I should know when to keep my trap shut.

I have never heard of a CMU foundation referred to as CBS as it is in the title of this thread. Is that a common name in your area and what does it stand for (Concrete Block S…)?

1 Like

Concrete Block Stucco

1 Like

Gotchya. Thank you! The OP is referring to the stucco (or parge coating as I say). It’s been driving me nuts, lol.

1 Like

From the green fungal activity in most of the photos, it appears the foundation is experiencing a lot of hydrological pressure from excess rainwater being retained at the CMU’s and footings. Gutters and downspouts are recommended; proper placement, slope, and maintenance recommended if they already have a gutter system in place.

You are most likely incorrect. Again, and again, and again… For years.

Look at the moss/algae/growth at the outside corner, as it suggests excess moisture. A picture taken further back would easily settle that this is - Settlement.

1 Like

I was responding to Robert and then scrolled down to see your post.

A vertical crack due to earth loading or frost would be unusual except when the whole wall leans in and cracks occur (usually) near an inside foundation corner such as shown in our photo below

crack wider at the top

“When you choose a specialist, you have chosen your diagnosis and treatment.” Edward Tufte

I have to agree with those that said either-or. Heaving of the ground at that crack location could cause a wider gap at the top, and settlement at the left corner of that foundation could also cause the same. Hard to say, other than recommend a qualified professional and let them analyze further. Not sure if my eyes are deceiving me looking at the picture, but the block under the plate to the left of the crack looks just a bit higher than the block to the right of the crack. If it was heaving at the crack, I would think both blocks (left and right) would move up together - but, now I’m just being stupid and speculating :slight_smile:

1 Like