Originally Posted By: Thomas Tracy This post was automatically imported from our archived forum.
My foundation was just poured (10 inch concrete w/ vertical and horizontal rebar). I live in NE Pennsylvania. The temperatures were in the high 30’s to low 40’s at the time of the pour. That night it got down to about 18-20. I was apprehensive but the GC said everything would be fine and they would cover the forms with plastic which i realize has no insulative properties. The temp was in the single digits approx. 72 hours after the pour.
Now I see a continuous crack about six feet high on a nine foot wall (for lack of a better word because to me it looks like a surface crumbling that is not too deep) around the whole interior foundation wall except for one section. It is more noticeable in some spots than in others. The GC says this is because there were two pours- one about an hour and a half after the other and this is where the first pour melded with the second pour. There is no bulging or bowing nor is there any offset.
I am naturally suspicious although the GC has a sterling reputation. Can someone advise me? Merely a homeowner who knows very little... Thanks!
Originally Posted By: cmccann This post was automatically imported from our archived forum.
Got a picture? Is the cracking horizontal? Is so we have been discussing this on another thread. I’m no expert about temps and concrete, but I can tell you that the “Cold Pour” (2 different pours) is very common and they often leave a trail of where the two pours meet. Consult your local building inspection department for the current requirements in your area. The rebar sounds good.
Originally Posted By: kmcmahon This post was automatically imported from our archived forum.
Usually they cover the forms with blankets or under tarps with heaters. Green concrete can easily freeze at those temps, with the water molecules expanding and cracking the concrete.(not to mention stopping the curing process)
Hard to tell if this did affect your pour, but like Chuck said, it would help to see a photo of the “problem” area.
Originally Posted By: mkober This post was automatically imported from our archived forum.
A “cold joint” in a concrete wall is undesirable but occasionally unavoidable. For the low placement temperatures described, it sounds like your GC might have added calcium or some other set accelerant (had it added at the batch plant–it should show on the delivery ticket). Otherwise it’s not likely that initial set would have taken place in 90 minutes in a 10-inch wall. The wall also should have had consolidation performed by mean of one or more spud vibrators, which when done properly will help eliminate cold joints by projecting through the fresh mud into that placed earlier. If it were my wall that had a significant cold joint (which will result in a weakness plane as well as a source of water intrusion), I would ask the GC how HE intends to correct HIS problem. You should be able to tell rather easily if the cold joint is serious by simply tapping on the cured concrete adjacent to the joint with a steel-handled hammer or geologist’s pick, and then progressively moving your taps farther away (vertically) from the joint–you’ll hear a difference in tone made by the hammer if the joint is anything more than a surface imperfection.
Originally Posted By: Thomas Tracy This post was automatically imported from our archived forum.
I have pictures but am at a loss as to how to post them. It is without a doubt a cold joint issue from all the info I have gathered here. Happy Holidays!
Originally Posted By: jmichalski This post was automatically imported from our archived forum.
Thomas,
When you post, there are boxes bleow the subject line, and above the text box you are typing in. One of them says "Img".
That is to add an image. Click it and it will walk you through how to set it up and submit it.
Basically: 1) click "upload a new image"
2) browse until you find where the file is stored, then click it and click "Upload"
After that, it asks whether you want to post it as an external link or embedded. Doesn't matter which you choose. One will add a link we cna click, the other adds an actual picture.
Originally Posted By: kmcmahon This post was automatically imported from our archived forum.
Fortunatly or unfortunatly for home inspectors, we just let you know about the problem. Solutions are best left to the specialists, like a fouondation specialist or your arch/engineer.
Originally Posted By: jpope This post was automatically imported from our archived forum.
and will not allow cold joints in structural concrete.
In my experience, in an area of high seismic activity, this condition would require an engineered correction that may well include a two-sided horizontal saw cut at a specified depth and height, followed by removal of the upper portion of the concrete (by jackhammer) and re-pouring of the top of the wall. Additional requirements may be considered for water proofing or sealing of the wall where an unanticipated joint may cause concern for water/moisture penetration.
The cost of this "extra work" would be absorbed by the responsible party(s). The contractor - for poor scheduling, or the concrete company - for poor timing.
Again, my experience is in large commercial applications rather than residential. I may be over-reacting a bit. 
-- Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738
Poor workmanship is my call, but I’m told it’s the “norm” for basements.