Horizontal Crack in Residential Basement Wall 2

[DaveAtkins]

I have inspected numerous residential basements, but I observed something recently that has me puzzled. See the attached photo.

Normally, I see hairline, VERTICAL shrinkage cracks in basements. They are almost inevitable, and are rarely a concern. Horizontal cracks generally ARE a concern, because they usually indicate a flexural failure of the wall.

However, as you can see in the photo, the wall is not bowing inward. Also, the crack is located near the top of the wall, where one would presume the bending moment is less.

It doesn't appear to be a cold joint.

Any ideas?

DaveAtkins

 

[BAretired]

It seems unusual that the crack remains horizontal all the way to the corner. Usually, the crack would split into a pair of diagonal cracks (a yield line pattern) if caused by bending. It is a mystery. Perhaps the wall was struck by a bulldozer during backfilling.

BA

 

[oldestguy]

Could be a cold pour joint. Also shrinkage on the inside might be more likely somewhat more than outside part. Shrinkage there would tend to bow the wall out.

 

[bridgebuster]

It could be a cold joint. It's hard to tell from the photo but the "crack" appears to be leaking efflorescence. I've seen leaching like that on the bottom of new bridge decks. Perhaps the mix was a bit wet when the concrete was placed.

 

[dik]

Not sure what's up... appears to be too high up for it to be a flexural tension crack from soil pressure. Do you have any historical information?

Dik

 

[XR250]

Also, looks like the joists are parallel so bracing at the top of the wall would be minimal. As such, flexural crack is unlikely. I am thinking cold joint as others have suggested.

 

[DaveAtkins]

Our client owns another residence on the same street, identical in size to the residence mentioned above.

See the attached photo. In this basement, it appears the wall WAS done in two pours, and the cold joint is just about in the same location as the crack in the other residence.

Does this lend credence to our cold joint theory?

DaveAtkins

 

[JAE]

I would say yes. Great detective work!

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[Leftwow]

WOW, I'm glad I read this!

 

[dhengr]

DaveAtkins:
Given your second photo, that horiz. crack on the interior would seem to make sense. With a cold joint at that elevation, you can’t even count on the little inherent tensile strength that conc. does have. There isn’t even much bldg. D.L. on that wall. Then, those walls are regularly under-reinforced and likely with the rebar at the center of the wall if any exists. Finally the top of the wall is tied to the first fl. diaphragm to some extend, so any inward movement, of the wall, due to soil pressure will very likely show up as you see in your first photo, by a small opening of that cold joint. Your first photo also seem to show some interior finish on the conc. wall which might show the joint opening movement, in a much more pronounced way, as you see in the first photo.

 

[DaveAtkins]

Yes, the basement wall in the first photo is painted.

Now I need to decide what to recommend. I am thinking epoxy injection, but I would need to justify the moment capacity.

DaveAtkins

 

[dhengr]

DaveAtkins:
I’d suggest that you/they watch the crack for some extended period of time, over various seasons, and see if it hasn’t actually settled down, maybe by bringing some rebar into play finally. Draw the outline of your level on the wall in a few places, just as you are holding it in photo1. Watch for and measure any movement or changes out-of-plane, from end to end of your level, same locations each time. Also, measure the crack width at a number of places; vert. lines across the crack and horiz. lines across the vert. lines 1" apart, and watch for any changes to 1.05 or 1.1", or not. There are actually some gages on the market that will do this. If you don’t see much/any change, then you have some confidence in saying that your epoxy repair will primarily be cosmetic, and any moment cap’y. is less meaningful. Everyone is always impatient for an instant answer and solution, but these kinds of problems don’t usually have quick and perfect answers.

 

[oldestguy]

If anything I'd do one vertical line at the center and two horizontal at 1" spacing. Chances are nothing will ever be needed in the way of reinforcing, injecting, etc.,

 

[dik]

I've usually drilled a hole on either side and driven a couple of concrete nails into them. I use a digital calipers to measure any movement.