(To the tune of “Pop! Goes the Weasel)
Corner pops are small sections at the corner of a slab that break off and are about as common a hot weather in a Texas summer. Most slab homes and even many pier and beam homes have at least one corner that “pops,” or breaks off at some point. This often raises concerns for buyers who worry that this is an indication of foundation movement or structural problems. To be fair, it is a piece of the foundation, and it is clearly broken.
The good news is that corner pops can be fixed without much trouble and are not, at least by themselves, an indication that there are structural issues or problems with the home.
When showing these cracks to a client, I will frequently turn around and point to the same crack on the house next door. As home inspectors, we note and include corner pops in our reports so that our clients are aware of and have better understanding of what is causing corner pops to occur.
There has been some discussion in the home inspector community about whether this item should really be included in the Walls section or remain in the Foundation section. It is generally our policy to keep them under Foundations because that is where most people look for it.
At a recent home inspectors’ conference, I was talking to some home inspectors from different parts of the county and they were baffled by this issue, indicating that it may not be something that you would see as frequently in other parts of the country.
So, what are these things and why are they so common in our area?
First, it is important to understand that the exterior brick is not a structural component of the wall. It looks pretty and keeps the house from floating away but does not support the attic, roof or other structural components.
Second, brick and concrete have different thermal expansion properties. That is, they expand and/or contract at different rates when they heat and cool. So, on a warm summer afternoon, the brick in the wall is going to expand; so is the concrete of the foundation. This expansion is not pretty small, but the difference in the expansion of the brick and the concrete is enough to allow them to move differently.
Third, there is, or is supposed to be, a barrier between the brick and foundation. Typically this barrier is a black poly or plastic. Sometimes you can see a little bit of the black plastic sticking out between the brick and foundation on new houses. However, because of the way this plastic is installed, it is often missing at the corners (see example pictures below).
So, here is what happens: the plastic barrier is missing from the corner. The brick of the wall and the concrete of the foundation are in direct contact and bond together. Then we get a warm Texas day (read hotter than you-know-where), and the brick expands more than the concrete… and “Pop! Goes the corner.”
Should I repair corner pops?
To repair or not to repair a corner pop is often just a matter of personal preference. It is my opinion that there are only a few instances where it is important to repair this damage.
The vast majority of these cracks are too small to make any difference; however, we do sometimes see a corner pop that has some cracking in the brick that it supports. If the section of the foundation that has broken off is too big, it can leave the brick unsupported. If the brick is settling a little in conjunction with a corner pop, then I would recommend repair to make sure that the brick has adequate support and does not continue to crack.
With thanks to Bill Sallade at Lighthouse Engineering for his input and diagrams.