Lets see what you guys think….. I was called to a home to see why the slab in basement is cracking all over the place.
Home was completed in march of 2001. The slab was poured in the middle of a cold day in jan.2000 about 16 degrees outside with no heat during or after the pour.
The slab was stress cut into 16’x20′ sections, is 4″ thick poured with fiber mesh but no wire mesh or plastic.
It was poured in two sections with the second section in good shape.
The first is cracking all over ,with the cracks running a avg distance of 10′.
they transfer across the stress cracks slightly shifted but within a foot each time.
The 1st section is also whiter in color.
Some of the slabs where the stress cuts are, appear to be different in height as in they have heaved or moved to some degree.
My thinking is the french drains haved failed and the slab is heaving. There is an area I can view under the slab and there is water during this thaw we are having. Only thing that gets me is it survived the first thaw it faced and only recently during its second thaw has failed.
Any thoughts?
Replies
Thoughts:
Why no heat with a 16 degree pour?
Pretty large sections. What was the base? Any stone? Sand? Compaction? Insulation?
Relying a lot on fibers to handle bad pour conditions, subsurface water problems and large size with no further reinforcement
Different mix for different sections?
Mainly I don't like the cold temperature pour.
Edited 4/15/2002 11:08:54 AM ET by Mad Dog
Thanks for reply Mad Dog. Around here most basement floors are poured in one shot with no joints or cuts. 4" on base and mesh with plastic.
At first I thought It was a nice effort on his part to cut in stress cuts throughout until I began to look closer.
Almost seems he kew it would happen.
He did know it would happen and tried to disguise it.
The soil under the pour was frozen and possibly heaved up at the time he poured. Settling and movement has allowed the cracks. They could alsdo be partly caused by shrinkage of the slab as it cures. The whiter colour is a hint that his portion was wetter. A wetter pour will be more inclined to have shrinkage cracks.
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