Posted by: dave on June 12, 2000 at 16:20:34:

In Reply to: Re: concrete cracking Posted by: Jeff on June 04, 2000 at 12:48:57:

: : Last year I had a concrete patio slab poured.
: : This spring I noticed severe cracking on 1/2 of the slab(the part of the building where the worst cracking occured was where 2 corners of the slab were up against the house) I asked the contractor why this happened and he claimed it was due to improper grading. I asked someone from the cement company and she said that with proper prepping of the soil and a 2-4" stone fill would not cause a cracking problem. I also asked the person who did my driveway what he thought and he noticed that there was no expansion felt between the concrete and the building. I do know for a fact that there was no soil prep when the forms were laid. Any info would be appreciated.

: David
: It seems to me that you got info from three places but that none of the three got together to provide it all. Not having expansion may cause the cracks but not having the sand or stone base will also. Improper grading unless he is thinking about the soil compaction should not have been a real problem. You do not give a size for the slab so I am unsure as to how many control joints or cuts should have been made to help control the cracking. For more information on pouring a slab check out the Concrete Network's web page they have a very good article on this.
: Jeff

Jeff,

the size of my slab is 11' 5" X 20' with a control joint in the middle. what prep should have been done before they laid the concrete??

thanks

Followups::

: : : Last year I had a concrete patio slab poured. : : : This spring I noticed severe cracking on 1/2 of the slab(the part of the building where the worst cracking occured was where 2 corners of the slab were up against the house) I asked the contractor why this happened and he claimed it was due to improper grading. I asked someone from the cement company and she said that with proper prepping of the soil and a 2-4" stone fill would not cause a cracking problem. I also asked the person who did my driveway what he thought and he noticed that there was no expansion felt between the concrete and the building. I do know for a fact that there was no soil prep when the forms were laid. Any info would be appreciated. : : David : : It seems to me that you got info from three places but that none of the three got together to provide it all. Not having expansion may cause the cracks but not having the sand or stone base will also. Improper grading unless he is thinking about the soil compaction should not have been a real problem. You do not give a size for the slab so I am unsure as to how many control joints or cuts should have been made to help control the cracking. For more information on pouring a slab check out the Concrete Network's web page they have a very good article on this. : : Jeff : Jeff, : the size of my slab is 11' 5" X 20' with a control joint in the middle. what prep should have been done before they laid the concrete?? : : thanks

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