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Foundation Stabilization and Repair/basement floor diagonal crack wall to wall


cracked slab
cracked slab  
cracked slab 2
cracked slab 2  
QUESTION: Hi. I would sincerely appreciate any help you could give me.  I live in New York, just north of NYC.  Home is 20 years old. Please refer to attached photos.  The crack has been present since we moved in but it now appears larger, and the area between the crack and both walls has definitely settles and slopes downward.  There is no seepage into the basement.

The home foundation is cinder block, and the basement is poured concrete. The vertical cinder blocking is NOT cracked at all, just the floor. I don't like the fact that this is a small corner and there is a pitch already which may get worse over time.
 I would like your unbiased expert opinion by someone other than someone who can potentially fix this issue.  If there is no problem with the structural integrity of the home, must this be repaired?  How can I tell if this crack affects the structure or is just cosmetic? If there is settling under this corner of the home requiring excavation and reinforcement of the blocks?
I smell huge money being spent here and I hope I am wrong.

Thanks so much
 ps I made the pix very small for downloading ease.

    The basement concrete floor is normally poured independent and separate from the foundation and walls. Floor cracking will not hurt your walls. Since you said the floor has been cracked for 20 years it's possible that organic material was mixed in with the underlying fill material. It cracked soon after being built because of consolidation and now is settling further due to the organics breaking down. ( first best guess )
Second guess...water is beginning to undermine this area from below due to a water table change. I would break open a section and dig into it a bit to see what is below. If it is dry it is consolidation. If it is wet you need to find out why and drain it!...before it undermines your footing.

Best regards, jim

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cracked slab 3
cracked slab 3  
QUESTION: Thank you so much for your help.  I certainly feel less panic now, knowing the walls and floor can crack independently of each other and mean different things. however I mistakenly left out something which may impact the answer you gave me.  Although the home is 20 years old, we have only lived here for 3 years.  I noticed the crack when we moved in, but it has been a very cold winter here, lots of sub zero and snow and ice etc.  I don't inspect the crack on a regular basis, but the crack now appears significantly wider than I have ever noticed.  Also it always just appeared as a crack. Now it is apparent just by looking that the corner segment of the pour is sloping away from the rest of the pour.
So someone has to come in, remove the broken piece down to the earth?
Sorry for my mistake and I so appreciate your time.


     If you want to inspect below the floor to see what is happening you need to remove a section and then replace it. If you just want to raise the slab back to level you could have it slabjacked. Slabjacking is the process of drilling 1" holes through the slab and then pumping it with an engineered material to fill any voids and then lift it. An experienced vendor is critical or the slab could be damaged from overpressurization...or if you have an internal subfloor draintile, it could be filled with material and rendered useless.

See this link for some examples:

Foundation Stabilization and Repair

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Jim Hise


I am the owner of EXPERT BASEMENT REPAIR in Cleveland, Ohio. see WWW.EXPERTBASEMENTREPAIR.COM for more helpful links, pricing and information on repair work and products I can identify the reasons for movement or cracking in home foundations, basements and walls. I am familiar with most waterproofing and water control methods. I am familiar with and have installed Ramjack, Dixie MacLean, and A.B.Chance™ helical and push pier systems, including tiebacks, steel beams, and rod and grout repair and also several carbon fiber stabilization products. I am currently certified for Fortress carbon fiber installation and have performed carbon repair in the greater Cleveland and Northeast Ohio region for 14 years. Please remember to tell me what city you live in to help me answer your question up front!


20 years of structural foundation fault identification and most repair and stabilization methods. I introduced Fortress carbon fiber to this region of Ohio 14 years ago. I am always on site and involved in order to monitor each project I am responsible for. I have seen high pressure sales tactics used on homeowners over the years to buy on the very first contact. The most dominant ads on this site are good examples. My experience is that you need to be very careful when having these companies in your home.

Waterproofing magazine issue #2

Associates degree...and the school of hard knocks! Formerly certified by A.B.Chance company from 1993-2005. I have a construction and home improvement background for almost 35 years. I bought, restored and resold distressed property. I worked with 4 different foundation repair companies and am familiar with most methods. I also worked for a waterproofing company for several years. I teach ongoing education classes for home inspectors, adult education and Realtors in foundation fault identification and repair.

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Hundreds of residential, commercial and some industrial.

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