Dear Tim,
We are having a house build and they put the foundation last week. The
tempurature was -5 c. We went to look at it and there were some cracks. I
happened to read a letter that someone wrote to you about there cracks on
the foundation wall, it looks like the same ones that you said are cold
seam cracks. Is this a big problem and what should we do?
Cold Seam Crack
Summary: Cold seams in a poured concrete foundation can occur if the flow of concrete is interrupted. The foundation seam is where part of the concrete dries while waiting for more concrete to be poured.
DEAR TIM: The builder we hired to build our house just finished pouring the foundation walls on Monday. It was a very hot day with temperature in the 90's. After the forms were removed, to my dismay, I found these V-shaped lines in the wall. Are these cracks in the wall?
I got very worried and called the builder. He said these are not cracks and nothing to worry about. I asked a neighbor and he also said not to worry. Still, I am not convinced because I didn't see these lines when I look at basement walls of other new construction in town. Should I worry about structural damage and/or water leakage? To prevent later, I did ask the builder to spray the waterproofing UTC foam on top of the tar. Any advice on what else I can do? Thank you very much! Liang F., Westport, CT
DEAR LIANG: Looking at your photograph, these lines look like cold seams. Poured foundation walls can have cold seams where one batch of concrete gets hard while the next concrete truck is making its way into the job site. Or if the flow of concrete was stopped in one area while being poured in another. There may not have been enough workers to keep the concrete flowing properly.
These are potential weak spots in your foundation. They may be okay if there is enough reinforcing steel, or rebar, in the concrete.
Cold seams can be caused by delays in pouring the foundation. PHOTO CREDIT: Liang Feng
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Close-up of concrete cold seam. PHOTO CREDIT: Liang Feng
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Comments:
Bruno 04 Dec 2007, 18:47
AsktheBuilder 04 Dec 2007, 18:56
Bruno,
The best advice always is to call in a residential structural engineer.
R.Hill 20 Oct 2008, 13:55
My home is six years old, we now see water coming in along the edge of the
basement floor. Our home is built into a hill and the water that comes down
the front of the house is where the leak is occurring (where the wall meets
the floor). What would be the best way to seal this area?
abdallah 18 Feb 2009, 12:51
hello.
im a civile engineer my self and some times during a raft pour the batching plant faces a problem so the flow of concree is a affect, the raft had enough reinforcement, but the cold joints truly scares me View all comments |
