What is Corner Pop?

What is Corner Pop? Is it a Sign of Foundation Problems for My Home?

The corner of your home (or a possible home you want to buy) looks terrible. Like, a “what is going on here” kind of terrible. It literally looks like the concrete corner of the home has either broken off down near the ground or that it could break off because it is cracked quite a bit. 

This issue is aptly named “corner pop” and looks like the corner has “popped” off your house. Homeowners tend to worry that it signals a foundation problem and contact foundation repair companies for information.

Anchor Foundation Repair

At Anchor Foundation Repair, we have seen “corner pop” many times in our 35+ years in business in the Brazos Valley and field questions about it. While this issue can be present in a home with foundation issues, it is not caused by foundation settlement and is not a telltale sign of foundation problems either.

In this article, we will identify, describe, and show examples of what corner pop looks like and explain what causes it. We will further discuss why it is not a definitive sign of foundation problems.

What Does Corner Pop Look Like?

Corner pop affects the concrete beams that meet at the corner of a slab-on-grade foundation home near the ground. Whatever home you are seeing this problem on will also be a brick home. This is a specific issue that “pops” up with brick homes that have slab foundations. 

On some houses, the whole corner will have come completely off of the house between the ground and where the brick veneer begins. In other homes, it is cracked on both sides of the corner and looks like if you hit it really hard with a hammer that it could break away. It could also just be showing as a crack on one side of the corner or the other. 

We’ve put together a few photos to illustrate what you might see . . . 

Examples of Corner Pop

What Causes Corner Pop?

Corner pop is caused by two things in combination with one another. As in, you have to have both situations happening at the same time. It’s not one or the other, it’s both together. 

  1. Heat expansion in brick walls, plus
  2. No barrier or poor separation between the slab foundation and the brick mortar 

Let’s explain these two situations a bit more so that you can see how they “work together” to cause corner pop.

1. How Heat Expansion in Brick Walls Contributes to Corner Pop

Corner Pop close up

Brick walls expand when it gets warmer outside, this is a well-established fact. So, we know that brick will expand, but the side of your home is not just made of brick. At the bottom, the slab foundation is made of one solid piece of concrete and it does not expand the way that brick does. So you have something that expands resting on top of something that doesn’t expand. 

Brick expansion causes a shearing force that pushes the brick walls out towards the corners of the home. The slab does not move along with the brick because it is stuck in the ground and also doesn’t expand like the brick wall does (or if it does expand it’s at a much lesser rate). 

When you have brick on both sides of the corner, the corner can crack and pop off because it is getting this shearing pressure from both sides concentrated on that corner point. The expanding brick is so strong that it cracks the concrete and then pushes that little piece right off the house.

Brick masons and builders know about expansion in bricks and walls and can compensate for it. Expansion joints are planned in brick walls to allow the brick walls to expand without causing damage to the home. Expansion joints are most often seen in longer runs of brick walls. 

Unfortunately, expansion joints don’t protect against corner pop, they only prevent cracked bricks. So the cause of corner pop has another *underlying* problem that we will read about in the next section.

2. How Barrier Problems Contribute to Corner Pop

Builders and brick masons have figured out that this difference in expansion exists between brick and concrete. So the way to solve this problem is to put some kind of barrier between the brick wall and the slab foundation. Different materials have been used over the years for this purpose. Usually, it’s some kind of specialized construction paper, plastic sheath, or house wrap material.

repaired corner pop

The barrier keeps the brick from being directly connected to the slab. Then the brick can slide across the foundation and expand as needed. This avoids putting extra pressure on the slab and prevents corner pop.

If a mason does not put in the barrier at all, then the problem of corner pop comes up. There was a time where some builders might not have known that this was *a thing* – this is why building codes change over the years – problems happen and then they figure out why and do better. 

So homes of a certain age might have this problem more prevalently, like around the time when slab foundations became *all the rage* in the 50s and 60s.

Also, poor builder workmanship or a barrier that didn’t get put in correctly can create contact and adhesion between the brick wall and the foundation and cause corner pop. So, sometimes it can just be sloppy work and a barrier that is not completely in place that causes the problem. Unfortunately, human error or lack of attention to detail can be the culprit.

Is Corner Pop a Sign of Foundation Problems?

Hopefully the explanations above about what causes corner pop will help answer the question of whether corner pop is a sign of foundation problems or not. If I’ve explained it right, then I hope it is now clear that corner pop is not a symptom of foundation problems, especially if it’s the only sign, symptom, or worry you have. 

Corner pop is most often just a symptom of expansion differentials and a lack of separation between brick and concrete when the home was built. Occasionally, corner pop could indicate a sag in the middle of a wall, but other foundation settlement symptoms would likely be present as well.

Corner pop and other workmanship issues in a home foundation
This foundation has other workmanship issues in addition to corner pop.

Corner pop does not all by itself signal foundation problems. That is not to say that you won’t *ever* see corner pop on a home that has foundation problems though. Sometimes homes just have more than one problem with different root causes at the same time. 

This can especially be true in workmanship issues. If a builder cut corners or made mistakes in one area, they might have done so on other parts of the home as well.

The True Signs of Foundation Problems

So if corner pop is not a sign of foundation issues, then what is? Great question, I was hoping you would ask. There are a few telltale signs of foundation problems like diagonal cracks in drywall, stair-step cracks in brick, trim separations, and problems with doors or windows opening, closing, or latching properly. 

Signs of foundation problems

It’s never just one sign that indicates a foundation problem, it’s a combination of signs presenting together.

There are also other misleading signs like corner pop that tend to make homeowners think they have a foundation problem when they might not.

At Anchor Foundation Repair, we have been repairing foundations in the Bryan, College Station, and other Brazos Valley communities like Navasota and Brenham since 1985. We know the true and false signs of foundation problems in our area and can tell you about them.

Here’s an article with a picture guide that answers the question, “Is Foundation Repair Needed? Real and False Problem Signs,” that can help decode the symptoms you are seeing around your home.