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Looking for accurate cost information related to foundation cracks?

Perfect, you’re in the right spot. In this guide, you’ll learn:

  • When foundation cracks are serious problems
  • What the different types of foundation cracks are
  • The causes of a cracked foundation
  • How to prevent and identify foundation damage
  • How to save money on foundation cracks

Your home’s foundation is under immense stress and soil pressure from all sides. It supports the weight of your entire home, it resists the weight of dirt and water from the sides, and it prevents moisture from getting in through the bottom.

As the ground around your foundation settles, shifts, gains moisture, and freezes, the resulting foundation movement commonly leads to the formation of cracks in your concrete. Many homeowners are unaware of the severity of these cracks, and they often don’t know the cause of the problem or the solution.

Below, I’m going to go over the different kinds of cracks that can occur in your concrete foundation, the common causes of each, and prevention and repair methods that will keep your home and everyone inside safe.

When Are Foundation Cracks Serious?

Several different types of cracks can occur in concrete walls and floors, and the severity of the problem is often indicated by the kind of crack and the location in your basement or crawlspace.

We’ll get into specifics below, but generally speaking, stair-step and horizontal cracks are the most dangerous and are always a cause for concern.

Other types of cracks can result from normal settling, but any crack that continues to grow or that reaches ⅛” wide at any point is a serious issue and should be addressed immediately. Additionally, cracks that are wider on the top than the bottom should be a cause for concern.

What Are The Types Of Foundation Cracks?

Cracks can appear on any portion of your foundation floor or walls, and the position and size are good indicators of the underlying problem. Below, I’ll detail the different types of foundation cracks and how to identify them.

Vertical Cracks

A vertical crack, also commonly referred to as a shrinkage crack, is one that travels up your foundation wall vertically. They can be slanted a bit, but usually not more than about 20-30 degrees. These cracks are often signs of normal foundation settling and should simply be sealed using proper waterproofing methods.

Horizontal Cracks

Horizontal cracks appear on your foundation walls, and they travel horizontally without spanning concrete blocks vertically. These cracks should be taken very seriously, as they can lead to significant loss of your foundation’s structural integrity, especially if they span corners of your foundation. This type of crack needs to be inspected by an engineer and may require underpinning or other foundational reinforcement.

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Diagonal Cracks

Diagonal cracks are similar to vertical cracks, but they run at an angle greater than 30 degrees and less than 75 degrees. These can be signs of larger problems and should be inspected by a structural engineer or foundation specialist, especially if they span the corners of your basement or crawlspace. The cure may just be to seal them with masonry caulk, or they may require structural reinforcement.

Stair-Step Cracks

Stair-step cracks look like a set of stairs, as they run horizontally between concrete blocks, then vertically, then horizontally again, and so on. These types of cracks are severe and can indicate major loss of structural integrity. They should be inspected by a professional and usually require underpinning or some other form of reinforcement.

Basement Floor Hairline Cracks

Basement floor hairline cracks are very thin and form on your concrete slab. These cracks often spread once formed, but they’re usually not a significant cause for concern. They should be sealed with a waterproof epoxy, especially if they grow to ⅛” wide.

What Causes A Foundation To Crack?

Wall cracks and floor cracks can be caused by many things, and the type and location of the damage is often a good indicator of the underlying cause.

Vertical cracks on walls and hairline cracks in your poured concrete foundation are almost always caused by the natural settling of your home or the ground around your foundation. This process is normal and isn’t a problem unless the cracks leak or grow to ⅛” in width.

Horizontal cracks are caused by excess hydrostatic pressure on your basement wall from soil or water. If you don’t have gutters and downspouts installed, or if your property isn’t graded for proper drainage, water soaks the ground outside your home and puts excess weight on your foundation walls.

Horizontal cracks can also be caused by frost heave, which is external pressure created by freezing water in the soil.

Diagonal cracks are caused by differential settling, which is when certain portions of your home or the ground outside settle at different rates. These cracks are common if your soil conditions change quickly due to weather or improper drainage, or if your home is set on clay soil.

Stair-step cracks are also caused by more severe differential settling, usually due to too much or too little water in the soil around certain parts of your home. These cracks most often result from a sinking corner of your foundation.

What Are The Warning Signs For A Crack in Your Foundation?

Aside from a visual inspection of your foundation walls and floor, there are some other warning signs of damage you can look out for. Because your entire home relies on your foundation’s integrity, the warning signs are typically seen in your home’s structure.

For example, a sagging, bowed, or wavy roof can be a sign of foundation damage or instability. Multiple doors or windows getting stuck or swinging opened or closed on their own often indicate uneven foundations. Cracks forming at the corners of your windows or doors also point to foundation issues.

Sloped floors or creaking in your floors could indicate normal settling, but they could also be warning signs of foundation damage.

Lastly, a slanted chimney or bowing in your basement’s concrete wall or drywall are often good indicators of serious structural problems that should be addressed immediately.

How To Prevent A Foundation From Cracking?

Normal settling of your home and the dirt around it can’t be avoided, but thankfully, the resulting issues - indicated by hairline floor cracks or vertical cracks - aren’t severe.

More involved foundation issues like horizontal, diagonal, or stair-step cracks are almost always caused by too much water in the soil around your foundation. The best way to prevent these is to implement proper drainage practices.

First, ensure your property is appropriately graded to direct water away from your home. Next, install gutters and downspouts to collect and divert rainwater away from your foundation. If water build-up is still an issue, consider installing a drainage system like a French drain to move groundwater away from your foundation walls.

When Should You Repair A Crack In Your Foundation?

The simple answer to this question is: always! I recommend repairing all cracks in your foundation, regardless of the severity.

Repairing horizontal and stair-step cracks of any size in any location on your foundation walls is of utmost importance, as these will worsen over time and can lead to structural instability and even house collapse.

Vertical, diagonal, and basement floor hairline cracks should be assessed by a professional if their width grows to ⅛”. However, they should be sealed with a proper waterproofing epoxy regardless of width, as they can allow moisture in that can lead to mold formation and rot.

How To Save Money If You Have Cracks In Your Foundation?

The best way to save money on repairing cracks in your foundation is to get the damage inspected and fixed by a professional as quickly as possible. Foundation damage often gets worse and can result in much more extensive repairs that can be astronomically expensive. Getting the problem fixed early can help save you thousands of dollars in the future.

Check out the video below on fixing foundation cracks yourself:

Some minor foundation repairs - like sealing small vertical cracks or basement floor hairline cracks - can be DIY jobs, which will save you money on labor costs. However, if ever in doubt of the severity of the damage, it’s imperative you have a professional inspect it before doing any repair yourself.