Hey All — About to start a new build and I have a foundation contractor picked out. Price is right, posts lots of projects on social media, people comment on these posts positively and there are good reviews of the business — all seems pretty solid. However, I looked on their Facebook page today to see if they had any new posts and I saw the attached image on a new foundation they just poured. They seem to be psyched on it, but I couldn’t help but noticing the big diagonal looking crack.
I don’t know concrete or foundations, but this seems like an error, no? Hoping someone could enlighten me as to what this blemish is and if I would be concerned if it showed up on my foundation.
Appreciate it–
Replies
Looks like they had a second load of concrete come later than expected so the prior batch had already started to set. So a cold joint. So long as there was sufficient rebar it should be okay. Ask the structural engineer about it.
I agree.
It's what's called a pour line. It may not be a cold joint if the worker at the end of the pump hose had a partner with a vibrator "knitting" the 2 placements together.
These lines can be prominent depending on the concrete mix and form release agent used. Proper consolidation by vibrator tends to minimize the appearance.
Overall, if the lower layer placement was still plastic when the upper layer was placed, they "knit" together with minimal vibration and are not a structural defect.
[ Licensed P.E. w/over 50 years involved in the concrete construction industry]
Thanks for the details -- makes sense