A fellow I know has a house in southern NH he paid over a million dollars to have built.
His foundation is cracking horribly.
Over 30 years ago, I did a footing and 8 foot concrete walls in our barn that had no heat until 2 years ago.
I used a LOT of rebar, on 4" centers. One small crack I expected over a ledge all the rest still level and no other cracks.
Maybe the homeowner went down to check his basement and discovered existing cracks, maybe the blast helped reveal them.
i saw a “ask this old house” tv program on house foundation problems in new hampshire that are attributed to poorly mixed concrete...
I own a home at our farm that was built in 1946-47 and there are no foundation cracks (pier and beam with hardwood floors) in any of the original building. An addition was added in the 1970’s and there are some in the slab portion of it.
It depends upon a lot of things, soil type, rebar, the actual concrete mix, the content of the water, how much water in the original mix. The best concrete is placed not poured. How it is cured is very important too.