Foundation cracked after back fill

[MNCharlie1]

Hi everybody, my Wife and I are building a home, a two story with a walkout.We drove to the site tonight to see how the house is taking shape. The have poured footings, set block foundation, backfilled and started to frame the basement. While looking around we noticed a crack in the foundation from the very top course of block all the way to the footing. It's cracked through the center of blocks and also through mortar joints. How is something like this addressed? Does the wall need to be re-blocked or are there repairs for these situations? I would like to get opinions before I hear what they have to say. The builder hasn't said anything about it, but I think it has just happened yesterday or today. I have pictures and have contacted our Rep to see what they say.

Any advice is appreciated.
Charlie

 

[tony1851]

If the crack is roughly at the middle of the wall, and fairly even in width all the way down, it's probably due to shrinkage of the CMU work.
Not a structural issue, but might get water penetration depending on ground conditions.

 

[ree]

Unfortunately it is a structural issue, not least because the Minnesota winter (think Fargo) ground frost (equals ground movement) will find any weakness and move the wall - typically, it will bulge it in by some small degree each winter.

Did you happen to notice how the vertical rebar was set and came up from the footings?
Was any horizontal rebar tied in?

Careless back filling with a machine might be responsible, but how it happened is almost irrelevant to your case - the crack is there.

By cracking, the wall will have split any external damproofing application which, of course, will render the basement unusable due to, as above, water penetration.

If you are framing the basement then do you have a framed shell above?

Take care of this issue immediately by having an on-site meeting with all parties - repair might be possible, or it might require a wall re-build from footing to mud-cill.
Without pics its hard to comment, sometimes a PE has to be called in.
Sometimes its resolved on site but dont you start making the calls. Why? Because you are not qualified.

If this is a "Buy Off Plans" sort of semi-tract operation then the "Rep" is not your friend. Who appointed the GC or the Super?

 

[MNCharlie1]

Thanks for the responses. I'm just trying to get as much info as I can. I'm not a home builder, I'm not sure what things happen during the process.

I didn't notice the rebar settings. I know vertical rebar was placed, not sure ow it was set, don't recall the horizontal.

The basement was not going to be finished at this time. There is no framed shell above right now. No slab poured in the basement. I thought the slab should be poured and joists attached to sill before backfill?

The builder has assigned the Super.

Thanks again for any input.

 

[ree]

Typically,

for a block basement house the footings are formed and re-barred.
vertical rebar, for threading thro the blockwork, is tied into the footing rebar.
footings poured.
blockwork is built up, grouting in as they rise.
horizontal rebar tied in at intervals.
mud cill bolted on at correct height.
slab membrane in, and slab poured - sometimes the slab runs thro, and the blockwork is built off the slab.
the shell is then framed up to ridge.
backfilling takes place when the structure is braced and solid

There are variations but the above is a rough guide.

Maybe you can say a bit more about the organisation and site - big, small, one off or tract? Super's usually run a number of builds.

 

[MNCharlie1]

I loaded a couple images. Maybe that will shed some light. One shows roughly where the crack is. The other gives an idea of the site. The crack is on the other side of the block where it is circled.

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• MNCharlie1
• 8 May 2014
• 1

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• MNCharlie1
• 8 May 2014
• 1

 

[ree]

A pic of the actual crack would help. What i can see doesn't indicate any serious fault - i was under the impression, my mistake, that the crack had split the blockwork from outside to inside.

There's a little slope which indicates that not too much backfilling would have been required.

Everything else in the build in progress seems perfectly ordinary, and done to Code.

 

[MNCharlie1]

Here is a pic of the crack. I meant to upload one...

Untitled

• MNCharlie1
• 8 May 2014
• 1

 

[ree]

Thanks for the pic, I notice that the wall is braced to the right of the crack. No other bracing is showing in the pics.

Still hard to tell: that crack could be a shrinkage crack, as suggested above.

Footings should only be poured on undisturbed soil, or you are into pile driving territory.

If there was make up soil at one end of the footing, then the footing might sink a little at that end. Does the crack continue through the footing?

Part of your foundation blockwork has been damproofed - why not all?

 

[MNCharlie1]

The crack doesn't continue into the footing, at least that I can see.

The pics I've sent aren't in any particular order. I was just sending them to give you an idea of the lot. The whole foundation has been sprayed.

An engineer is meeting with the Supervisor to take a close look at it. I hope all is well.