Basement wall crack

Originally Posted By: jbushart
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I have a cold joint running horizontally along the entire length of a basement wall. At one corner, approximately five feet before the wall ends, a crack begins along the joint and widens as it makes a 90 degree to the next wall and moves up the wall to the top of the foundation. The widest part of the gap is 3/16 ", which is at the top of the foundation. While this indicates movement and requires further evaluation by a specialist, I am curious for my own edification the likelihood of the crack/movement continuing the length of the cold joint. Is this common?


Originally Posted By: kmcmahon
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Need pictures!



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Originally Posted By: jbushart
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http://www.nachi.org/bbsystem/usrimages/N/Norhtwest_B_wall_crack.JPG ]


Here is one of several pics.


Originally Posted By: mmasek
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This crack could be the result of a cold joint. The truck delivering the concrete being poured into the forms might have run out and during the wait for more the “old” concrete might have set and the new concrete did not stick or bond to it. If the walls have rebar in them, this will help to hold the pours together, the call for a structural engineer was a good one.


Originally Posted By: dvalley
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James,


Welcome to NACHI.

We had just discussed a similar crack...
![](upload://me4MtRe3nGBGET8vgZY42XGj9kl.gif)


--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."

Originally Posted By: mkober
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James,


Welcome aboard!

Just because a crack is 3/16" wide does not necessarily indicate that movement of the member is taking place. It may mean that the contractive forces acting within the member have manifested themselves in the form of a very visible crack. Without knowing all of the facts, a calculated guess would be that the contractor did too good of a job applying external heat in one area while the concrete was attaining initial set--causing abnormal shrinkage to take place (although usually, concrete shrinkage is evidenced by a series of narrower, often random cracks in an area). Conditions can be made worse by other factors, such as calcium chloride added to the mix to hasten initial set, forms stripped too soon, and even applying external loads (backfilling the foundation) without temporarily bracing the interior of the walls or waiting until the house framing deadload is in place. Taking a series of non-destructive concrete compression readings in the area of the crack as well as other areas would indicate whether or not the problem is localized in the mix itself. And, yes, cold joints are typically weakness planes, making a logical place to observe cracking if other forces are at work.


--
Michael J. Kober, P.E. and H.I.

"NACHI Member and Proud Of It!"

Originally Posted By: roconnor
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mkober wrote:
Just because a crack is 3/16" wide does not necessarily indicate that movement of the member is taking place.

In my opinion concrete shrinkage and thermal movements in concrete would only account for a portion of that movement in a residential foundation, and even then it's not likely that movement will all occur at one location (due to restraint from footings, drag on the soil, etc.). Plus the crack is reported to get wider at the top, which is not consistent with just shrinkage cracking.

The ACI 224 series of concrete standards has some good info for those specialists evaluating concrete cracks ... but it's very technical, and ties in a lot of other design standards.

For a new home have your licensed design professional look at that, and give you a written determination and recommendations.

Just my opinion and 2-nickels ... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)


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Robert O'Connor, PE
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I am absolutely amazed sometimes by how much thought goes into doing things wrong