Multiple Foundation Cracks

[Mike Lamb]

I have never seen so many poured concrete foundation cracks in a single home - vertical, horizontal, diagonal. It was like a jigsaw puzzle. 30 yr old house. Many were epoxy injected but not all. Except for some minor inward bulging at a couple places, the foundation was dead-on plumb. No noticeable problems upstairs.

Thoughts as to why this occurred? Too soupy a mix?

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[John Dirks Jr]

Pulled the forms and back filled to early?

[mjr6550]

Concrete that is too wet can create a lot of cracks, but it looks like more is going on there. It appears that there is a horizontal joint near the top of the foundation wall. I see that when they use 8-foot forms and want a foundation wall 9 or 10 feet high. There may have been a cold joint there, especially if adding height was an afterthought (excavated too deep, owner changed their mind).

The random cracking is too closely spaced for typical shrinkage cracks. I have seen that before when the foundation was backfilled too early, as John said.

[Rob Amaral]

Heads up.. that looks like a condition well-known in a certain part of CT..

I'll try to google-search it for you..

Something to do with bad aggregate reacting and expanding and such.. 'standby for more'..

[Rob Amaral]

http://www.nbcconnecticut.com/troublesh ... 61181.html

It might be something like this.. ("might") Certainly has same cracking pattern in one of your photos..

[Mike Lamb]

Thanks. Could be connected. Quebec also has had problems with pyrrhotite in concrete.

http://www.davidpublishing.com/davidpub ... 925785.pdf

[Charlie R]

Possibly a poor mix, too wet, could have been poured with the temperatures too low, the concrete is hot when you pour but if it got down into the teens that night you can have freeze spots that turn into cracks. Won't show up for years. Can also be that the rebar was rusted, did you see any spalling? That is usually the rebar (reinforcing rods).

[mlparham]

Possibly a poor mix, too wet, could have been poured with the temperatures too low, the concrete is hot when you pour but if it got down into the teens that night you can have freeze spots that turn into cracks. Won't show up for years. Can also be that the rebar was rusted, did you see any spalling? That is usually the rebar (reinforcing rods).

I would suspect a hot mix.