Thread: What caused this

I was wanting some opinions as to what might have caused this. Hydrostatic pressure causing a crack? Poor concrete work? Most of the foundations we inspect are covered with brick veneer so we don't see that many exposed stem walls other than the garage. Of the ones I do see, I don't recall ever seeing this. There were no cracks or signs of movement in or outside the 35 yr old house.

Similar Threads:

• Any concern caused on this deck built
• backdrafting caused by exterior chimneys
• Corrision on a connection caused water heater replacement
• PA man says improperly installed dryer vent caused fire - Southeast Texas Record

Originally Posted by Frank Bombardiere

I was wanting some opinions as to what might have caused this. Hydrostatic pressure causing a crack? Poor concrete work? Most of the foundations we inspect are covered with brick veneer so we don't see that many exposed stem walls other than the garage. Of the ones I do see, I don't recall ever seeing this. There were no cracks or signs of movement in or outside the 35 yr old house.

Looks like just the outside Parge coating is cracking and not the foundation.

I see wood grain lines in that, looks like it was not parged, just left exposed after the forms were removed.

In which case that looks like spalling from the steel possibly being too close to the exposed edge and rusting.

Spalling is not good.

Frank,

You got any more pics. ? Maybe with rust stains ?

Deem be the straightest most uniform wood grains I've ever seen .

There were no rust stains or visible rods. To the left of this area the wood grain was very evident and no cracks. I am leaning towards spalling. I did not take other pics. It was like this in an area on the opposite side of the house to. I thought it looked like spalling and advised them verbally that it likely needs parging before it gets worse, but I am now writing the report and wanted to get some opinions to help me out. Thanks

Spalling. I see it alot on old slabs.

I believe it is a poor mix of concrete. Too much water, water added to the mix at a later time or not enough cement in the mix, Concrete will fail in this manner.

Originally Posted by Frank Bombardiere

I thought it looked like spalling and advised them verbally that it likely needs parging before it gets worse, but I am now writing the report and wanted to get some opinions to help me out. Thanks

It's too late for pare coating.

That crack means the concrete on one side of the crack (the side toward you) is loose from the side toward the rest of the slab.

The only repair is to chip out all of the loose and spalled concrete and repair it with new concrete. They typical way I've see it done is they pneumatically place (shoot) gunite to build it back up. Kinda like shooting a gunite pool (see photo on: REED Gunite Machines. ) .

Also: http://www.sika.gr/PDF/Concrete%20Repair.pdf

The "cause" is that the steel in the footing rusted, pushing the concrete away from the rest of the footing (thickened slab edge). That slab as been structurally affected and degraded.