My wife and I are having a home built in Yuma, Az. The cocrete pad was poured 60 days ago. Two weeks ago, I noticed random patterned cracks (about 4 mm wide) throughout 70% of the slab. Now, the cracks are 1/8" wide. The cracks continue to propagate. At what width can I consider the slab a total loss or that its structural integrity is compromised?