MANY hairline cracks in foundation

So I inspected a 66 yr old home today here in the high desert in Central Oregon. Somebody did some kind of skim coat to the foundation. In the crawl I only found one “larger” flaring crack, roughly 3/16 wide at the top. So i believe the foundation may have had some spalling. Hoever i have no way to verify that.

Okay finally the question, The west side of the house that gets all the afternoon sun showed these small cracks. I tapped on it in many places with a piece of metal and it didn’t sound weird or hollow it actually sounded quite solid…

Any ideas what created these cracks? Did whatever product they used dry to quick? Was it to thick? I really have a limited knowledge on concrete repairs.

Just as a “fun extra” since you read this far, I’m pretty sure concrete products are not an approved repair to rotten wood siding. Also found on the same house.


Applied thick and dried too fast. I would not put this in the report, however. Just call it out for repair. Possible spalling or some deformity.

Mortar on wood is just a flipper special fixer-upper.


Those cracks are more than likely caused from what is called plastic shrinkage. When concrete is poured too wet, cracks like these can form as the concrete sets. The water cement ratio was too high. See it all the time in new construction when a pump is used to pour the concrete and the pump primes in the wall form. If it was grouted after the fact, there wasn’t enough or any sand added to the mix. Just Portland cement and water will do this if not mixed properly.