Large Vertical Cracks in Basement Wall

[AraEng]

I recently visited a single-family house with multiple wide cracks in the concrete basement wall. It's quite old and no reinforcement is visible. The client shared that they have minimal water intrusion through the cracks and I can see why that is. There's an 8-foot addition beyond the basement wall that cause the water to run away from it for the most part. I doubt if there are any immediate structural concerns and don't think any remedies beyond proper sealing of the cracks are necessary. But my question is what could have possibly caused such cracks. There are no signs of settlement or any other cracks in the floors above. Any thoughts? I've included a picture.

 

[le99]

I think it is a shrinkage crack that has widened after subjecting to seepage for a long time.

 

[dik]

Judging from the crack and the colour of the concrete, it's pretty weak concrete, too.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[le99]

@dik has pointed out the potential weakness of the wall, the concrete may contain a large number of calcium deposits that may cause the wall to deteriorate further. I suspect/guess that, on top of seepage, the wall is mostly moist during the high water season. If that is the case, there is no easy way to fix this problem, short of waterproofing the exterior face. If unattended, the wall can crumble away sooner or later.

 

[bones206]

My first guess is a shrinkage crack that hinged open under out-of-plane pressure when the aggregate interlock friction was overcome. There is rebar visible near the bottom of the crack. It looks like it might be severed.

 

[MotorCity]

I disagree with the shrinkage crack postulation. Shrinkage cracks vary from hairline to slightly larger. Shrinkage also occurs soon after construction. If this is an old structure, why is it being reported as a problem now? This is a gaping discontinuity in the wall, not to mention the large hole at the bottom of the wall. The rebar poking through suggests that there is a structural element that ties into this wall on the other side. Since this is residential, there is probably not alot of vertical load on the wall. I bet the damage occurred during construction (perhaps during the addition) and an excavator or other piece of equipment hit the wall or ran into it. It also looks like there is spalling or a groove that follows the crack on the surface. Not sure if this occurred because of the crack or maybe it was a poorly executed repair attempt?

 

[Brad805]

Why? Poor concrete, zero reinforcement, poor backfill, poor floor diaphragm connection.... Unless you have an impermeable cover at the top of the fill water finds its way into the backfill. What instigated the investigation? Perhaps a pending sale? In many cases the repair involves digging it up and constructing new foundations.

 

[bones206]

The OP said there were multiple wide cracks. So that implies a systemic problem or cracking that occurs in a pattern, like shrinkage.

I also suspected the addition playing a role. A pre-existing shrinkage crack would provide a weak plane that opened up under a new out-of-plane load.

 

[PEinc]

I agree with MotorCity. The "crack" looks more like a wall failure than a shrinkage crack. The "crack" looks very old and maybe had some black waterproofing added some time ago. The "crack" could have gotten worse when the addition was excavated.

http://www.PeirceEngineering.com

 

[bones206]

I agree it's a wall failure now, but it could have started life as a shrinkage crack.

 

[nackra]

When was the farmhouse originally built? Maybe stone foundation was replaced with concrete in "sections" - butting up against stone... Just a thought. I agree - not shrinkage cracks!

 

[bones206]

Farmhouse?