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Re: large cracks in slab

To: "Scott Hall" <sch8489@garnet.acns.fsu.edu>
Subject: Re: large cracks in slab
From: "Keith Turk" <kturk@ala.net>
Date: Thu, 5 Dec 2002 22:32:14 -0600
Scott... Almost every single slab I've ever poured or seen has crack's..
it's a normal result of shrinkage in the first 28 days of curing.... if it's
56 days old it's most likely done shrinking....   ( your mileage may vary )

Now the normal size of the crack is porportional to the quality of the
concrete itself.... house slab's by BOCO, IBCO or SBCCI  allow for the use
of 3000 psi concrete.... or a 4.5-5 bag mix.... ( meaning there is
450-500lbs of cement per cubic yard )  bottom line if the water content for
that cubic yard was stretched to make it easier to pull ( float ) on the
rakes.... well that will cause it to shrink more.... ( by the way it's most
likely out of spec. and won't hurt a thing... but if your gunning for the
Builder this might be a wierd bone of contention )

Would I worry if it was my house.... hmmm most likely not so long as it was
set on a PURE flat situation... if the ground is sloping more then a foot or
so... well I'd be much more concerned.... not sure I'd be freaking out about
it... but I'd watch it for a while before I stuck down any high dollar
flooring and I'd make a point to the builder that I was concerned and going
to have the actual crack measured along it's distance for a couple of years
and he would sign a letter saying he understood my concern and would extend
the warranty appropriately...

Okay now for the Caulking.... I'd be fine with that.... but I'd also be okay
with a simple mortar mix type patch floated into the crack with say a screw
driver type device.... my thoughts being your more likely to get quality
penetration with cementatious products then you are with Caulk type
patches.... You do have to do something because water in some form or
fashion is going to migrate...

I'm a builder but don't do a lot of concrete work under houses.... I own a
concrete manufacturing business that makes veneer stone products... So what
I'm saying is mostly off the top of my pee brain... and keep in mind that
CRS stuff ...

Keith Turk
----- Original Message -----
From: "Scott Hall" <sch8489@garnet.acns.fsu.edu>
Cc: <shop-talk@autox.team.net>
Sent: Thursday, December 05, 2002 9:35 PM
Subject: large cracks in slab


>
> just got to see under the carpet in the new house...
>
> there are *huge* cracks in the slab (well, huge for somebody with a
> mortgage).  almost big enough to fit my little finger.  they're level, but
> the only cracks I'm used to seeing look like pencil lines.  these look
> like the slab is trying to slide away from itself.
>
> the plan was to put strip flooring down, but now I'm worried.
>
> my options range from caulk to cutting notches and putting bolts in.
>
> advice, anybody?  please?
>
> thanks.
>
> scott

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