View Full Version : Foundation crack
eshyde
Dec 13, 2008, 12:50 PM
My foundation was poured 5 days ago on the home I'm having built. There is now a crack that runs from the bottom where the dirt is on the left side up vertically and then runs the entire width of the house and continues vertically down to the bottom where the dirt is on the right side. Is this normal? The builder representative had someone grind the surface to see if it was a "surface" crack but the crack was still visible after the surface had been ground down. Does this sound like it's a problem? It's got me losing sleep.
twinkiedooter
Dec 13, 2008, 12:54 PM
Whoever poured this basement screwed up royally. The crack whether it be "surface" or not is going to cause you a LOT of problems. Anytime we've had poured basements for our modular homes that we sell, they have always cracked and caused leaking due to the Ohio ground holding too much moisture. You should have gone with the cinder blocks instead of the poured cement basement as your property obviously has too much water in the soil. Have this corrected NOW before your house is sitting on a basement that is leaking like a sieve. Don't listen to the guy who thinks it's a surface crack as he sounds like he is backpeddling to save his behind. The concrete could also have been "old or hot" as well and this could cause problems with it setting up properly.
KBC
Dec 13, 2008, 02:09 PM
Typically a concrete pour will crack,this is a quote from the local concrete contractor here where I live,He all but guarantees this.He compares it to the painters adage,oil paint will eventually crack or peal.(although painters have improved the process some with additives and such)
Putting that much weight on a newly excavated ground will undoubtedly have cracks.
As long as the pour has rebar or screening this crack won't have much movement.
Think of it as this,putting a thin piece of glass on an uneven rock, then put weight on the glass around the rock, the glass will break,right?
Same thing with concrete,it has to have a solid leveled(somewhat)ground to rest on,that's why digging and stone is applied to allow for imperfections and to spread the weight around.
If the stone under the pour was done wrong,like not enough to allow the weight to be (somewhat)evenly distributed,the concrete will break or crack.
If the ground(as twinkiedooter said) is wet or has soft areas the concrete will crack.That is why stone is installed,in hope that it will accommodate the imperfections in the subsurface.
Hard,solid un-giving surface verses soft or undesirable subsurface equals crack/split.
Hope this explains it for you,
KBC
21boat
Dec 13, 2008, 05:27 PM
28 years of pouring crete. Concrete is never the same twice. Crack Reasons:Pouring when its too hot or to cold. Also the time between trucks is cruical. Too much time between trucks creates a "cold joint" To help stop that, vibrate old to new lift pour A lot. A crack can from espically when the sun hits one part and it heats and expands to quickly and the other shaded part sits there. Believe it or not when a lot of water is added ( a 6 slump)it actually makes crete set faster. Concrete on perfect condations needs 30 days to harden at 70 degrees air temp. On commercial pours we hope for a 60% or better in a week of cure. It cures slower as the next weeks add time. You can dig one day and pour the next provided the ground is dry and mechanial tamped for compaction Jumping Jack Vib Roller. Back filling against the walls when its to green is almost a garuntee it will crack. It sounds like someon backfilled to quick. Proper size and the right amout of Rebar is a big. Heat is a big factor. In hot condiatios on big slabs / wall pours you HAVE to hose it down and keep it saturated for days. A crack of your size will awalys be a serious problem because of the horizontial ( shear). Crete is amazing for compression ( down pressure) It terable for shear( side pressuer) Ergo Rebar. Personaly I wouldmbe REAL concerned. A lot of conrete cracks through many many years od shift and settlement. Here for many we do prefab crete panels with sealed expansion joints. At this point I would spend the 1,500 or more for ( I hate to say this) Engineer and Stop all Construction. This is another example why A 10" concrete block walls work well.Your crack will never go away. 99% chance it will never go away. This 'Flake crack is only when the sun beats on a walk and the top surface lifts up towards sun a flake or spaw.The reason we use concrete walls is manily for compaction strenght, (commercial stories) I have spent part of my life jacking up buildings and replacing foundations walls. I think things were rushed ( horzintial crack) and if the temp changed at night you need to use concrete "warming Blankets" Which is very good at keeping the heat in while the create cures. A couple of years ago we poured In Jan And keep the blankets on and on the 2 day a blanket blew off. The next day a perfect vertical crack almost exactly where the blanket stayed on and the other blew off. It's that sensitive. I feel bad for you. Make the Call. Sorry! I would tear it all out and start over. Even if its was my Job and it happened to my coustomer. I would bite the bullet and spend the thousands of dollars and be able to sleep right. Even as 28 year prof. I/we are not perfect and nature always rules in my line of work. Hope this helps.
twinkiedooter
Dec 13, 2008, 08:34 PM
21 - You really explained the concrete situation very well. My late husband did a lot of concrete work and taught me a lot. He did a lot of highway work and there were many times when the concrete trucks were turned away for the Florida Turnpike project he was working on as the concrete was hot or too old to properly set up right. It never ceased to amaze me that the concrete plant would keep sending bad concrete for these projects. One day I counted 6 concrete trucks (in a row) that were sent back due to bad concrete!! You could have gotten a truckful of bad concrete as well as having too cold weather for the concrete to deal with and it just cracked under the stress.
Please have your project redone or you will definitely be sorry down the road once you have your house sitting on this "mess"
eshyde
Dec 14, 2008, 09:54 AM
I have a structural engineer coming Monday to check it out. Thanks for the advice :)
ballengerb1
Dec 15, 2008, 08:15 PM
All concrete cracks but your description of the crack is not normal so the engineer was a good idea. Listen to the engineers recommendation and not necessarily the concrete contractor on this one.