Wall Cracks Explained: Why They Happen and How to Fix Them

Worried about cracks in your walls? Here’s the truth — they’re almost always NOT a structural concern. In this video, we break down why wall cracks happen, what they mean, and how to fix them without hiring an engineer. The solution is simple — patch, paint, and redirect water. If you’ve been stressing over cracks in your drywall or stucco, this video will put your mind at ease. No panic. No overthinking. Just clear guidance to protect your home and your peace of mind.

Wall Cracks Explained: Why They Happen and How to Fix Them

Worried about cracks in your walls? Do you see a diagonal line across your drywall or stucco and wonder, 'Is this a big deal?' Well, I’m here to tell you — it’s not. Wall cracks are incredibly common and, in most cases, not a structural concern. So, let’s talk about why these cracks happen, how to address them, and what you actually need to worry about when it comes to your building’s safety and longevity.

Here’s the deal — most wall cracks happen due to differential settlement. When part of your foundation settles downward more than the rest, it creates a slight displacement throughout the entire building. Since walls stack on top of the foundation, they experience shearing forces that cause diagonal cracks. This is completely normal. It’s the building’s way of rebalancing itself, redistributing forces, and settling into a new equilibrium.

To understand this better, let’s quickly look at how your foundation works. Around the perimeter of your building is a continuous concrete footing that supports the exterior walls. But inside, you have post-and-beam systems that carry the floors above. Each post sits on its own isolated footing that isn't tied to the perimeter foundation, so it can settle downward independently from the rest of the foundation.

Why do footings settle? It’s usually because of either soil compaction, where softer soil compresses downward, or erosion, where ground water, leaks, or broken pipes wash soil away, causing voids beneath the foundation.

When any of this happens, isolated footings sink, and everything above it — posts, beams, walls, floors — all shift downward. That’s why you’ll see cracks on multiple levels and notice your floors may have a slight slope.

The good news? It’s not a structural issue. Your building isn’t going to fall down. Here’s how to handle it:

Patch and paint — For interior walls, use basic joint compound and paint. For stucco exteriors, use an epoxy filler to keep water out, then paint it. This prevents water infiltration that could lead to dry rot.

Redirect water — Check your downspouts and gutters. If water is draining near your foundation, connect the downspouts to drainage lines, or use corrugated pipe to extend them at least 4 feet away from the building.

Check for broken pipes — If you have persistent settlement, call a plumber scope the pipes under your house. A cracked sewer or water line can cause erosion that leads to foundation settlement.

If you have moisture issues, take action. Excessive water under your home can keep eroding soil. If you’re on a slope or hill, you’ll naturally have more groundwater movement. Here’s what you can do:

Install a French drain that catches underground water and redirects it away from your property.

Add a sump pump to remove pooling water in your crawl space and keep things dry.

These actions will keep your soil stable and prevent further settlement.

Okay, there’s a small chance cracks might be from something other than settlement. It’s rare, but it happens. Examples include:

Dry rot — If your wood framing has extensive dry rot, it can crush, shift, and create cracks.

Structural failure — Occasionally, a structural element might fail. If you’re unsure, have a building inspector take a look and tell you if there’s an issue. You won’t need an engineer — a contractor can pull a repair permit and fix it “in-kind”, meaning, fix it the same way it was originally built. This is faster and avoids the engineering and plan review process.

Sloped floors and wall cracks often go hand in hand. They’re a sign of settlement, not structural danger. It’s a serviceability issue, not a safety issue.

Here’s the bottom line:

Wall cracks are not a structural concern.

They’re almost always caused by differential settlement.

Just patch, paint, and keep your building’s exterior waterproofed.

If water’s an issue, address the source with drainage or a sump pump.

If you suspect dry rot or structural failure, call a building inspector.

There's no need to lose sleep over wall cracks, they’re normal, they’re manageable, and you’re safe.

We hope this video gives you peace of mind. If you’ve got wall cracks, you’re not alone, it's an incredibly common condition — and now you know what to do. Patch, paint, redirect water, and stay dry. It’s that simple.

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For more information or to learn more about our services, visit CityStructural.com. Thank you for watching and we’ll see you next time.