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burnselk 09-19-2009 04:20 PM

Foundation and Cement Question
I'm having my home foundation wall dug completely up to expose the wall because I'm having some "bowing" and "tipping" problems which have caused horizontal and vertical cracks in the interior wall.

I was told in my contractor's proposal that every other cinder/concrete block would be filled with cement after the rebar is put in. The contractor said this would make 'columns' that would stabilize the wall and keep it from moving further. He also will waterproof the foundation wall and install a footer drain.

My question is this: How do I know for certain that every other block will in fact be "filled completely" with concrete? I'm told the cement will be poured into every other block very wet so it can drain down to the footer.

Am I out of line to ask for proof that the cement made in all the way to the bottom (the last block) and that the cavity is full of cement. I suggested putting a small hole in the bottom block so I could "see" the cement at the bottom. I'd also like for them to use a vibrator to make sure the cement goes to the holding a chipper against the rebar for instance. Otherwise will it go all the way down and fill all of the hole that has rebar?

inspectorD 09-19-2009 05:03 PM

Aside from being there all the time, you will have to rely on the contractor to do their job.
Having the mix to runny will cause issues with the mix failing in time.
Hiring a third party to watch what is going on would be your best alternative,keeps them honest if someone who knows what to look for is lookin right over their work.

burnselk 09-20-2009 06:21 PM

Help me find the quantity of concrete needed
Could someone tell me how many cu. yds. of cement will be needed to fill "one of the core cavities" in an 8 foot high wall of cinder blocks? This cavity will also have an 8 ft. length of rebar inserted in it prior to pouring in the cement.

After I find this answer I can determine how much cement will be needed for the entire wall.

mudmixer 09-20-2009 07:48 PM

You do not fill the cores of blovk with "cement".

You do not use eithe mortar ot concrete.

You use grout that has very little (if any) coarse aggregate and should be very wet (8" to 1" slump), compared to concrete that is drier and has rock in it and has a slump of 3" to 5". Slump is measured as the height a 12" cone of the mix drops when the mold is removed.

Grout is intentionally wet and fine to insure that the voids are filled and the rebar is fully enveloped. The excess water in the mix is absorbed by the masonry units and provide and ideal curing environment.

One of the biggest problems with grout is using a material that is too dry or vibrating forms or rebars, that does little good if the grout is too coarse and bridges and does not really fill where intended.


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